Programs to be executed by communication systems, control devices, base stations, terminal devices, and computers.

Abstract

To provide a communication system capable of reducing processes or resources for a connection determination in a millimeter wave band or a terahertz band.SOLUTION: In (m) pieces of base stations and (n) pieces of terminal devices, in the case of m<n, regarding all the (m) pieces of base stations, beam scan processing is cooperatively executed for executing regarding all beams scanned by one base station reception processing for the (n) pieces of terminal devices to synchronously receive a frame transmitted from one base station using one beam while scanning the beams on the basis of a scan schedule. In the case of m≥n, regarding all the (n) pieces of terminal devices, beam scan processing is cooperatively executed for executing regarding all the beams scanned by one terminal device reception processing for the (m) pieces of base stations to synchronously receive a frame transmitted from one terminal device using one beam while scanning the beam on the basis of a scan schedule.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a communication system, a control device, a base station, a terminal device, and a program for execution by a computer.

Background Art

[0002] Conventionally, for each pair of a base station and a terminal station, one forms a beam and transmits while scanning, and the other receives omnidirectionally and then measures the signal quality in the selected directivity (Patent Document 1).

[0003] More specifically, the millimeter-wave base station 300 transmits packets for channel quality measurement while changing the directivity, and the terminal station 400 estimates the signal quality using the packets for channel quality measurement received omnidirectionally (non-directionally). Next, the terminal station 400 transmits packets for channel quality measurement while changing the directivity, and the millimeter-wave base station 300 estimates the signal quality using the packets for channel quality measurement received omnidirectionally.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Patent Document 1, there is a problem that when attenuation or noise is large (when it cannot reach with only one-way beam formation) such that communication is impossible unless both the base station and the terminal form beams for transmission and reception, the directivity cannot be selected.

[0006] To address this problem, when both sides form and scan beams for transmission and reception, the number of trial times increases to [the number of base stations × the number of base station beams × the number of terminals × the number of terminal beams], resulting in an increase in overhead.

[0007] Therefore, according to an embodiment of the present invention, a communication system capable of reducing processes or resources for connection determination in the millimeter wave band or the terahertz band is provided.

[0008] Also, according to an embodiment of the present invention, a control device used in a communication system capable of reducing processes or resources for connection determination in the millimeter wave band or the terahertz band is provided.

[0009] Furthermore, according to an embodiment of the present invention, a base station used in a communication system capable of reducing processes or resources for connection determination in the millimeter wave band or the terahertz band is provided.

[0010] Furthermore, according to an embodiment of the present invention, a terminal device used in a communication system capable of reducing processes or resources for connection determination in the millimeter wave band or the terahertz band is provided.

[0011] Furthermore, according to an embodiment of the present invention, a program for causing a computer to execute in a control device of a communication system capable of reducing processes or resources for connection determination in the millimeter wave band or the terahertz band is provided.

[0012] Furthermore, according to an embodiment of the present invention, a program for causing a computer to execute in a base station of a communication system capable of reducing processes or resources for connection determination in the millimeter wave band or the terahertz band is provided.

[0013] Furthermore, according to an embodiment of the present invention, a program for causing a computer to execute in a terminal device of a communication system capable of reducing processes or resources for connection determination in the millimeter wave band or the terahertz band is provided. [Means for solving the problem]

[0014] (Composition 1) According to an embodiment of this invention, the communication system comprises m (where m is an integer of 2 or more) base stations, n (where n is an integer of 2 or more) terminal devices, and a control device. The m base stations perform wireless communication. The n terminal devices are connected to some or all of the m base stations. The control device is connected to the m base stations by backhaul lines. The control device transmits a scanning schedule to the m base stations for coordinating the scanning of the beam between the m base stations and the n terminal devices. The m base stations transmit the scanning schedule received from the control device to the n terminal devices.

[0015] When m is less than n, m base stations and n terminal devices cooperate to perform a first beam scanning process for all m base stations, in which the n terminal devices synchronously scan the beams to receive frames transmitted from one of the m base stations using one beam based on a scanning schedule, and the first beam scanning process is performed for all beams scanned by one base station. When m is greater than or equal to n, The m base stations and n terminal devices work together to perform a second beam scanning process for all n terminal devices, in which the m base stations synchronously scan the beams to receive frames transmitted from one of the n terminal devices using one beam, based on a scanning schedule.

[0016] (Configuration 2) In configuration 1, when m is less than n, in the first reception process, all but one of the m base stations maintain a sleep state based on the scan schedule.

[0017] (Composition 3) In configuration 2, when m is less than n, in the first reception process, the frame includes destination identification information, source identification information, and source beam number.

[0018] (Composition 4) In configuration 3, when m is less than n, in the first reception process, each of the n terminal devices that received the frame detects the received signal strength at the time of receiving the frame and also detects the source beam number from the frame. It then associates the detected source beam number with the received signal strength to create a measurement result and transmits the created measurement result to the base station to which it is connected. Each of the n base stations connected to each of the n terminal devices transmits n measurement results to the control device.

[0019] (Composition 5) In configuration 4, when m is less than n, the control device performs a connection determination between the base station and the terminal device based on n measurement results received from the n base stations.

[0020] (Composition 6) In configuration 5, the control device identifies the beam number with the highest received signal strength among the interconnected base stations and terminal devices based on n measurement results, and determines that a beam with a received signal strength equal to or greater than the threshold is connectable when the received signal strength when receiving a frame with the identified number is equal to or greater than the threshold.

[0021] (Composition 7) In configuration 1, when m is greater than or equal to n, in the second receiving process, all but one of the n terminal devices maintain a sleep state based on the scanning schedule.

[0022] (Composition 8) In configuration 7, when m is greater than or equal to n, in the second reception process, the frame includes destination identification information, source identification information, and source beam number.

[0023] (Composition 9) In configuration 8, when m is greater than or equal to n, in the second reception process, each of the m base stations that have received a frame detects the received signal strength at the time of receiving the frame and also detects the source beam number from the frame. It then associates the detected source beam number with the received signal strength to create a measurement result and transmits the created measurement result to the control device.

[0024] (Composition 10) In configuration 9, when m is greater than or equal to n, the control device performs a connection determination between the base station and the terminal device based on m measurement results received from each of the m base stations.

[0025] (Composition 11) In configuration 10, the control device identifies the beam number with the greatest received signal strength among the interconnected base stations and terminal devices based on m measurement results, and determines that a beam with a received signal strength equal to or greater than the threshold is connectable when the received signal strength when receiving a frame with the identified number is equal to or greater than the threshold.

[0026] (Composition 12) In configuration 1, the frame is transmitted using a beam in the millimeter-wave band or a beam in the terahertz band.

[0027] (Composition 13) Furthermore, according to an embodiment of this invention, the control device is a control device used in any of the communication systems of configuration 1 to configuration 12, and comprises a creation means and a communication means. The creation means creates a scanning schedule for scanning beams by coordinating m (where m is an integer of 2 or more) base stations and n (where n is an integer of 2 or more) terminal devices connected to some or all of the m base stations. The communication means is connected to the m base stations by a backhaul line and transmits the scanning schedule to the m base stations using the backhaul line. When m is less than n, the creation means creates a first scanning schedule for executing a first beam scanning process for all of the m base stations, in which a first reception process is performed for all beams scanned by one base station, in which n terminal devices synchronously receive a frame transmitted from one of the m base stations using one beam while scanning the beam. Furthermore, when m is greater than or equal to n, the creation means creates a second scanning schedule for all n terminal devices, which involves performing a second receiving process for all beams scanned by one terminal device, where m base stations synchronously scan the beams to receive a frame transmitted from one of the n terminal devices using one beam. When the creation means creates the first scanning schedule, the communication means transmits the first scanning schedule to m base stations using a backhaul line, and when the creation means creates the second scanning schedule, it transmits the second scanning schedule to m base stations using a backhaul line.

[0028] (Composition 14) In configuration 13, the control device further comprises a determination means. When m is less than n, the determination means determines whether a connection between a base station and a terminal device is possible based on a first measurement result measured at the n terminal devices when the m base stations and n terminal devices scan the beam according to a first scanning schedule. When m is greater than or equal to n, the determination means determines whether a connection between a base station and a terminal device is possible based on a second measurement result measured at the m base stations when the m base stations and n terminal devices scan the beam according to a first scanning schedule.

[0029] (Composition 15) In configuration 14, the first measurement result includes (x × y) received signal intensities and (x × y) beam numbers, which are the beam numbers of each of the x beams 1 to beams x, when each of the n terminal devices scans its beam to y (y is an integer of 2 or more) beams 1 to beams y and receives each of the frames transmitted using the x beams 1 to beams x. The second measurement result includes (x × y) received signal intensities and (x × y) beam numbers, which are the beam numbers of each of the y beams 1 to beams y, when each of the n terminal devices transmits a frame transmitted using the y beams 1 to beams y and each of the m base stations scans its beam to x beams 1 to beams x and receives each of the y beams 1 to beams y.

[0030] (Composition 16) Furthermore, according to an embodiment of this invention, the base station is a base station used in any of the communication systems of configuration 1 to configuration 12, and comprises a receiving means, a determination means, and a communication means. The receiving means receives a scanning schedule for scanning beams in cooperation with m (m is an integer of 2 or more) base stations in the communication system and n (n is an integer of 2 or more) terminal devices connected to some or all of the m base stations. The determination means determines, based on the scanning schedule, whether the base station is the source or destination of a frame using beams. When the determination means determines that the base station is the source of a frame, the communication means sequentially transmits frames using x (x is an integer of 2 or more) beams 1 to x, and when the determination means determines that the base station is the destination of a frame, the communication means receives a frame transmitted using one beam transmitted from one of the n terminal devices, scanning it through x beams 1 to x, for all n terminal devices.

[0031] (Composition 17) Furthermore, according to an embodiment of this invention, the terminal device is a terminal device used in any of the communication systems of configuration 1 to configuration 12, and comprises a receiving means, a determination means, and a communication means. The receiving means receives a scanning schedule for scanning beams in cooperation with m (where m is an integer of 2 or more) base stations and n (where n is an integer of 2 or more) terminal devices connected to some or all of the m base stations. The determination means determines, based on the scanning schedule, whether the terminal device is the source or destination of a frame using beams. When the determination means determines that the terminal device is the source of a frame, the communication means sequentially transmits frames using y (where y is an integer of 2 or more) beams 1 to y, and when the determination means determines that the terminal device is the destination of a frame, the communication means receives a frame transmitted using one beam transmitted from one of the m base stations, scanning it through y beams 1 to y, for all m base stations.

[0032] (Composition 18) Furthermore, according to an embodiment of this invention, the program is a program to be executed by a computer in the control device of any of the communication systems from configuration 1 to configuration 12, The creation means includes a first step of creating a scanning schedule for scanning a beam by coordinating m (where m is an integer of 2 or more) base stations and n (where n is an integer of 2 or more) terminal devices connected to some or all of the m base stations, The communication means is connected to m base stations via a backhaul line, and the computer is instructed to perform a second step of transmitting a scan schedule to the m base stations using the backhaul line. When m is less than n, The creation means creates a first scanning schedule for all m base stations, in which a first receiving process is performed for all beams scanned by one base station, in which n terminal devices synchronously scan the beam to receive a frame transmitted using one beam from one of the m base stations, and a first beam scanning process is performed for all beams scanned by one base station. When m is greater than or equal to n, The creation means creates a second scanning schedule for all n terminal devices, in which a second receiving process is performed for all beams scanned by one terminal device, in which a frame transmitted using one beam from one of the n terminal devices is received by m base stations in a synchronous manner while scanning the beam. In the second step, when the creation means creates the first scan schedule, the communication means transmits the first scan schedule to m base stations using the backhaul line, and when the creation means creates the second scan schedule, it transmits the second scan schedule to m base stations using the backhaul line.

[0033] (Composition 19) In configuration 18, the determination means causes the computer to perform a third step in which, when m is less than n, it determines whether a connection between a base station and a terminal device is possible based on a first measurement result measured at the n terminal devices when m base stations and n terminal devices scan the beam according to a first scanning schedule, and when m is n or greater, it determines whether a connection between a base station and a terminal device is possible based on a second measurement result measured at the m base stations when m base stations and n terminal devices scan the beam according to a first scanning schedule.

[0034] (Composition 20) In configuration 19, the first measurement result includes (x × y) received signal intensities and (x × y) beam numbers, which are the beam numbers of each of the x beams 1 to x, when each of the n terminal devices scans the beams to y (y is an integer of 2 or more) beams 1 to y and receives each of the x beams 1 to x. The second measurement result includes (x × y) received signal intensities and (x × y) beam numbers, which are the beam numbers of each of the y beams 1 to y, when each of the m base stations scans its beams to x beams 1 to x and receives each of the frames transmitted using y beams 1 to y.

[0035] (Composition 21) Furthermore, according to an embodiment of this invention, a program to be executed by a computer at a base station of any of the communication systems from configuration 1 to configuration 12, The first step is for the receiving means to receive a scanning schedule for scanning a beam in coordination with m (where m is an integer of 2 or more) base stations in a communication system and n (where n is an integer of 2 or more) terminal devices connected to some or all of the m base stations, The determination means performs a second step of determining whether the base station is the source or destination of a beamframe based on the scanning schedule, This is a program that causes a computer to perform the following steps: first, when a determination means determines that the base station is the source of the frame, it sequentially transmits the frame using x (where x is an integer of 2 or more) beams 1 to x; and second, when a determination means determines that the base station is the destination of the frame, it receives the transmitted frame using one beam of one of the n terminal devices by scanning it through x beams 1 to x, for all n terminal devices.

[0036] (Composition 22) Furthermore, according to an embodiment of this invention, a program to be executed by a computer in a terminal device of any of the communication systems from configuration 1 to configuration 12, The first step is for the receiving means to receive a scanning schedule for scanning a beam in coordination with m (where m is an integer of 2 or more) base stations in a communication system and n (where n is an integer of 2 or more) terminal devices connected to some or all of the m base stations, The determination means performs a second step of determining whether the terminal device is the source or destination of a beamframe based on the scanning schedule, This is a program that causes a computer to perform the following steps: first, when a determination means determines that the terminal device is the source of the frame, it sequentially transmits the frame using y beams 1 to y (where y is an integer of 2 or more); and second, when the determination means determines that the terminal device is the destination of the frame, it receives the frame transmitted using one beam of one of the m base stations by scanning it through y beams 1 to y, and this process is performed for all m base stations. [Effects of the Invention]

[0037] According to embodiments of this invention, the process or resources required for connection determination in the millimeter-wave or terahertz band can be reduced. [Brief explanation of the drawing]

[0038] [Figure 1] This is a schematic diagram of a communication system according to an embodiment of the present invention. [Figure 2] This is a schematic diagram of another communication system according to an embodiment of the present invention. [Figure 3] This is a schematic diagram of yet another communication system according to an embodiment of the present invention. [Figure 4] Figures 1 to 3 are schematic diagrams of the control device 1. [Figure 5] Figures 1 to 3 are schematic diagrams of base station 2. [Figure 6] Figures 1 to 3 are schematic diagrams of the terminal device 7. [Figure 7] This is a conceptual diagram of frame F. [Figure 8] This is a conceptual diagram of the beam formed by terminal device 7. [Figure 9] This is a conceptual diagram showing the beam scanning by the source and destination during the scanning period. [Figure 10] This is a conceptual diagram showing the scanning of the source and destination beams during a single scanning period. [Figure 11] This is another conceptual diagram showing the scanning of the source and destination beams during a single scanning period. [Figure 12] This is a schematic diagram showing the sequence when scanning a beam. [Figure 13] This is a conceptual diagram of the beam scanning sequence when the terminal device is the source of transmission. [Figure 14] This is the first conceptual diagram of the beam scanning sequence when the base station is the source. [Figure 15] This is a second conceptual diagram of the beam scanning sequence when the base station is the source. [Figure 16] This is a schematic diagram showing an example of a scanning schedule. [Figure 17] This is a schematic diagram showing another example of a scanning schedule. [Figure 18] This is a schematic diagram showing the measurement results. [Figure 19] This is a schematic diagram showing the measurement results aggregated by the control device 1. [Figure 20] This is a schematic diagram of connection destination information for base station APs and terminal devices STAs. [Figure 21] This is a schematic diagram of connection destination information for base station APs and terminal devices STAs, created based on the sets {1,1,1,2} and {1,2,1,1}. [Figure 22] This is a flowchart illustrating the operation of the communication system 10 according to an embodiment of this invention. [Figure 23] This is a flowchart illustrating the detailed operation of step S23 in Figure 22. [Figure 24] This is a flowchart illustrating the detailed operation of step S24 in Figure 22. [Figure 25] This is a flowchart illustrating the detailed operation of step S25 in Figure 22. [Figure 26] This is a flowchart illustrating the operation of control device 1. [Figure 27] This is a flowchart to explain the operation of base station 2. [Figure 28] This is a flowchart illustrating the detailed operation of step S57 in Figure 27. [Figure 29] This is a flowchart illustrating the detailed operation of step S58 in Figure 27. [Figure 30] This is a flowchart to explain the operation of terminal device 7. [Modes for carrying out the invention]

[0039] Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated.

[0040] Figure 1 is a schematic diagram of a communication system according to an embodiment of this invention. Note that Figure 1 is a schematic diagram of a communication system where the number of base stations is greater than the number of terminal devices.

[0041] Referring to Figure 1, the communication system 10A according to this embodiment of the invention comprises a control device 1, base stations 2 to 6, and terminal devices 7 to 9.

[0042] The control device 1 is connected to base stations 2-6 by a backhaul circuit (BHC). Terminal device 7 is connected to base station 2, for example; terminal device 8 is connected to base station 4, for example; and terminal device 9 is connected to base station 6, for example.

[0043] The control device 1 receives connection information [base station 2 - terminal device 7] from base station 2 via the backhaul line BHC, indicating that terminal device 7 is connected to base station 2; connection information [base station 4 - terminal device 8] from base station 4 via the backhaul line BHC, indicating that terminal device 8 is connected to base station 4; and connection information [base station 6 - terminal device 9] from base station 6 via the backhaul line BHC, indicating that terminal device 9 is connected to base station 6.

[0044] The control device 1 then stores the connection information [base station 2-terminal device 7], connection information [base station 4-terminal device 8], and connection information [base station 6-terminal device 9] in a database (=database 13, described later) in association with the time the connection information [base station 2-terminal device 7], connection information [base station 4-terminal device 8], and connection information [base station 6-terminal device 9] were received.

[0045] Furthermore, when the control device 1 performs a connection determination to determine the connection relationship between the base station and the terminal device, it stores connection determination information indicating that the connection determination has been performed in a database (= database 13, described later) in association with the time the connection determination was performed.

[0046] The control device 1 periodically determines whether or not to perform a connection determination to determine the connection relationship between the base station and the terminal device.

[0047] In this case, when it is time to perform a connection determination, the control device 1 refers to the stored connection information between the base station and the terminal device to determine whether a new terminal device has entered the communication system 10A. More specifically, the control device 1 determines to perform a connection determination if there is stored connection information associated with a time later than the time associated with the stored connection determination information, and determines not to perform a connection determination if there is no stored connection information associated with a time later than the time associated with the stored connection determination information.

[0048] When the control device 1 determines that it is time to perform a connection check, it coordinates the base stations 2-6 and terminal devices 7-9 to create a scanning schedule for scanning the beam, and transmits the created scanning schedule to base stations 2-6 via the backhaul line BHC.

[0049] Furthermore, when the base stations 2-6 and terminal devices 7-9 scan the beam in coordination, the control device 1 receives measurement results, including the received signal strength RSSI detected at base stations 2-6, from base stations 2-6 via the backhaul line BHC. Based on the received measurement results, it performs a connection determination, as described later, and generates connection destination information.

[0050] The connection information consists of connection information for base stations and connection information for terminal devices. Therefore, the control device 1 transmits the connection information for base stations to all base stations 2-6 via the backhaul circuit BHC, and also transmits the connection information for terminal devices to base stations 2, 4, and 6 to which the terminal devices are connected.

[0051] Each of the base stations 2 through 6 receives the scan schedule from the control unit 1 via the backhaul circuit (BHC).

[0052] Then, of the base stations 2-6, base stations 2, 4, and 6, which are connected to terminal devices 7, 8, and 9 respectively, transmit the scanning schedule to terminal devices 7, 8, and 9, respectively.

[0053] Then, base stations 2-6, in cooperation with terminal devices 7-9, execute a beam scanning process PCN_prs_2 (which constitutes the "second beam scanning process") for all beams scanned by one terminal device, which in turn executes a reception process R_prs_2 (which constitutes the "second reception process") for all beams scanned by one terminal device, based on the scanning schedule. This reception process R_prs_2 (which constitutes the "second reception process") is performed by base stations 2-6 while synchronously scanning the beams.

[0054] Then, in beam scanning process PCN_prs_2, each of the base stations 2 to 6 receives a frame transmitted from terminal devices 7 to 9 using a beam, detects the received signal strength RSSI when the frame is received, and detects the beam number of the beam, and generates a measurement result [{base station identifier, base station beam number, terminal device identifier, terminal device beam number}:RSSI] which associates {base station identifier, base station beam number, terminal device identifier, terminal device beam number} with the received signal strength RSSI.

[0055] Then, each of the base stations 2 to 6 transmits the measurement results to the control device 1 via the backhaul line BHC.

[0056] Base stations 2-6 receive connection destination information for base stations from control device 1 via backhaul circuit BHC.

[0057] Furthermore, base stations 2, 4, and 6, which are connected to terminal devices 7, 8, and 9 respectively, receive connection destination information for the terminal devices from control device 1 via backhaul line BHC, and transmit the received connection destination information for the terminal devices to terminal devices 7, 8, and 9, respectively.

[0058] Terminal devices 7, 8, and 9 each receive a scanning schedule from base stations 2, 4, and 6, respectively. Then, each of terminal devices 7, 8, and 9, in cooperation with base stations 2 through 6, performs the transmission of a frame using one beam at a time for all beams in the beam scanning process PCN_prs_2 described above, based on the scanning schedule.

[0059] Furthermore, terminal devices 7, 8, and 9 each receive connection destination information for terminal devices 7, 8, and 9 from base stations 2, 4, and 6, respectively.

[0060] Figure 2 is a schematic diagram of another communication system according to an embodiment of this invention. Note that Figure 2 is a schematic diagram of a communication system where the number of terminal devices is greater than the number of base stations.

[0061] Referring to Figure 2, the communication system 10B comprises a control device 1, base stations 2 and 3, and terminal devices 7 to 9.

[0062] The control device 1 is connected to base stations 2 and 3 by a backhaul circuit (BHC). Terminal devices 7 and 8 are connected to base station 2, for example, and terminal device 9 is connected to base station 3, for example.

[0063] When the control device 1 determines to perform a connection determination using the method described above, it creates a scanning schedule for scanning the beam in coordination with base stations 2 and 3 and terminal devices 7 to 9, and transmits the created scanning schedule to base stations 2 and 3 via the backhaul line BHC.

[0064] Furthermore, when the base stations 2, 3 and terminal devices 7-9 scan the beam in coordination, the control device 1 receives measurement results from base stations 2, 3 via the backhaul line BHC, including the received signal strength RSSI detected by terminal devices 7-9 and the beam number. Based on the received measurement results, it performs a connection determination, as described later, and generates connection destination information (consisting of connection destination information for the base station and connection destination information for the terminal device). The control device 1 then transmits the connection destination information (consisting of connection destination information for the base station and connection destination information for the terminal device) to base stations 2, 3 via the backhaul line BHC.

[0065] The control device 1 also performs the operations described in Figure 1.

[0066] Each of the base stations 2 and 3 receives the scan schedule from the control unit 1 via the backhaul line BHC.

[0067] Then, base station 2 transmits the scanning schedule to terminal devices 7 and 8, and base station 3 transmits the scanning schedule to terminal device 9.

[0068] Then, base stations 2 and 3, in cooperation with terminal devices 7 to 9, execute a beam scanning process PCN_prs_1 (which constitutes the "first beam scanning process") for all beams scanned by one base station, in which terminal devices 7 to 9 synchronously scan the beams and receive frames transmitted from one of the base stations 2 and 3 using one beam, based on the scanning schedule.

[0069] Then, in beam scanning process PCN_prs_1, each of the terminal devices 7 to 9 receives a frame transmitted from base stations 2 and 3 using the beam, detects the received signal intensity RSSI when the frame is received, and detects the beam number of the beam, and generates a measurement result that associates the received signal intensity RSSI with the beam number.

[0070] Then, each of terminal devices 7 and 8 transmits its measurement result to base station 2, and terminal device 9 transmits its measurement result to base station 3.

[0071] Then, base station 2 transmits the measurement results received from terminal devices 7 and 8 to control device 1 via the backhaul line BHC. Similarly, base station 3 transmits the measurement results received from terminal device 9 to control device 1 via the backhaul line BHC.

[0072] Furthermore, base stations 2 and 3 receive connection destination information (consisting of connection destination information for the base station and connection destination information for the terminal device) from control device 1 via the backhaul circuit BHC. Then, base station 2 transmits the connection destination information for terminal devices 7 and 8 to terminal devices 7 and 8, respectively, and base station 3 transmits the connection destination information for terminal device 9 to terminal device 9.

[0073] Terminal devices 7 and 8 receive the scanning schedule from base station 2, and terminal device 9 receives the scanning schedule from base station 3. Then, each of terminal devices 7, 8, and 9 works in cooperation with base stations 2 and 3 to perform the beam scanning process PCN_prs_1 described above, where they receive frames transmitted using one beam from one of the base stations 2 and 3, while scanning the beam, for all of base stations 2 and 3.

[0074] Then, each of the terminal devices 7 to 9 detects the received signal strength RSSI when it receives a frame, and also detects the beam number of the beam, and generates a measurement result that associates the received signal strength RSSI with the beam number.

[0075] Then, each of terminal devices 7 and 8 transmits its measurement result to base station 2, and terminal device 9 transmits its measurement result to base station 3.

[0076] Furthermore, each of the terminal devices 7 and 8 receives connection destination information for the terminal device from base station 2, and terminal device 9 receives connection destination information for the terminal device from base station 3.

[0077] Figure 3 is a schematic diagram of yet another communication system according to an embodiment of this invention. Note that Figure 3 is a schematic diagram of a communication system where the number of terminal devices is equal to the number of base stations.

[0078] Referring to Figure 3, the communication system 10C according to this embodiment of the invention comprises a control device 1, base stations 2 to 4, and terminal devices 7 to 9.

[0079] The control device 1 is connected to base stations 2-4 by a backhaul circuit (BHC). Terminal device 7 is connected to base station 2, terminal device 8 is connected to base station 3, and terminal device 9 is connected to base station 4.

[0080] When the control device 1 determines to perform a connection determination using the method described above, it creates a scanning schedule for scanning the beam in coordination with base stations 2-4 and terminal devices 7-9, and transmits the created scanning schedule to base stations 2-4 via the backhaul line BHC.

[0081] Furthermore, when the base stations 2-4 and terminal devices 7-9 scan the beam in coordination, the control device 1 receives measurement results from base stations 2-4 via the backhaul line BHC, including the received signal strength RSSI detected by terminal devices 7-9 and the beam number. Based on the received measurement results, it performs a connection determination, as described later, and generates connection destination information (consisting of connection destination information for base stations and connection destination information for terminal devices). The control device 1 then transmits the connection destination information (consisting of connection destination information for base stations and connection destination information for terminal devices) to base stations 2-4 via the backhaul line BHC.

[0082] The control device 1 also performs the operations described in Figure 1.

[0083] Each of the base stations 2-4 receives the scan schedule from the control unit 1 via the backhaul circuit (BHC).

[0084] Then, base station 2 transmits the scanning schedule to terminal device 7, base station 3 transmits the scanning schedule to terminal device 8, and base station 4 transmits the scanning schedule to terminal device 9.

[0085] Then, base stations 2-4, in cooperation with terminal devices 7-9, execute beam scanning process PCN_prs_1 for all base stations 2-4, which is performed for all beams scanned by one base station, in which terminal devices 7-9 receive frames transmitted using one beam from one of the base stations 2-4 while scanning synchronized beams, based on the scanning schedule.

[0086] Then, in beam scanning process PCN_prs_1, each of the terminal devices 7 to 9 receives a frame transmitted from base stations 2 to 4 using the beam, detects the received signal strength RSSI when the frame is received, and detects the beam number of the beam, and generates a measurement result that associates the received signal strength RSSI with the beam number.

[0087] Then, terminal device 7 transmits the measurement result to base station 2, terminal device 8 transmits the measurement result to base station 3, and terminal device 9 transmits the measurement result to base station 4.

[0088] Then, base station 2 transmits the measurement results received from terminal device 7 to control device 1 via backhaul line BHC. Base station 3 also transmits the measurement results received from terminal device 8 to control device 1 via backhaul line BHC. Furthermore, base station 4 transmits the measurement results received from terminal device 9 to control device 1 via backhaul line BHC.

[0089] Furthermore, base stations 2 to 4 receive connection destination information (consisting of connection destination information for the base station and connection destination information for the terminal device) from control device 1 via the backhaul circuit BHC. Then, base station 2 transmits the connection destination information for terminal device 7 to terminal device 7, base station 3 transmits the connection destination information for terminal device 8 to terminal device 8, and base station 4 transmits the connection destination information for terminal device 9 to terminal device 9.

[0090] Terminal device 7 receives the scanning schedule from base station 2, terminal device 8 receives the scanning schedule from base station 3, and terminal device 9 receives the scanning schedule from base station 4. Then, each of terminal devices 7, 8, and 9 works in cooperation with base stations 2 to 4 to receive frames transmitted using one beam in the beam scanning process PCN_prs_1 described above, while scanning the beam, based on the scanning schedule.

[0091] Then, each of the terminal devices 7 to 9 detects the received signal strength RSSI when it receives a frame, and also detects the beam number of the beam, and generates a measurement result that associates the received signal strength RSSI with the beam number.

[0092] Then, terminal device 7 transmits the measurement result to base station 2, terminal device 8 transmits the measurement result to base station 3, and terminal device 9 transmits the measurement result to base station 4.

[0093] Furthermore, terminal device 7 receives connection destination information for terminal device 7 from base station 2, terminal device 8 receives connection destination information for terminal device 8 from base station 3, and terminal device 9 receives connection destination information for terminal device 9 from base station 4.

[0094] As described above, in communication system 10C, base stations 2-4 perform the same operations as base stations 2 and 3 in communication system 10B shown in Figure 2, and terminal devices 7-9 perform the same operations as terminal devices 7-9 in communication system 10B shown in Figure 2.

[0095] Accordingly, in this embodiment of the invention, when the number of base stations is m (where m is an integer of 2 or more) and the number of terminal devices is n (where n is an integer of 2 or more), and the number of base stations m is less than the number of terminal devices n, as explained in Figure 2, the m base stations and n terminal devices cooperate to perform a beam scanning process PCN_prs_1 for all of the m base stations, which is performed for all beams scanned by one base station, in which the n terminal devices synchronously scan the beam and receive a frame transmitted from one of the m base stations using one beam based on the scanning schedule.

[0096] On the other hand, when the number of base stations m is greater than or equal to the number of terminal devices n, as explained in Figures 1 and 3, the m base stations and n terminal devices cooperate to perform a beam scanning process PCN_prs_2 for all of the n terminal devices, which is performed for all beams scanned by one terminal device, in which the m base stations synchronously scan the beams to receive frames transmitted from one of the n terminal devices using one beam based on the scanning schedule.

[0097] Figure 4 is a schematic diagram of the control device 1 shown in Figures 1 to 3. Referring to Figure 4, the control device 1 comprises a communication means 11, a control means 12, and a database 13. The communication means 11 is connected to a backhaul line BHC.

[0098] [Description of the control device 1 in the communication system 10A] The communication means 11 receives the scan schedule from the control means 12 and transmits the received scan schedule to base stations 2-6 via the backhaul line BHC.

[0099] Furthermore, when the communication means 11 receives the measurement result MR_k from base station k (k is 2 to 6) via the backhaul line BHC, it outputs the received measurement result MR_k to the control means 12 for all measurement results MR_2 to MR_6 transmitted from base stations 2 to 6.

[0100] Furthermore, the communication means 11 receives connection destination information (consisting of connection destination information for base stations and connection destination information for terminal devices) from the control means 12, transmits the received connection destination information for base stations 2-6 to base stations 2-6 via the backhaul line BHC, and transmits the connection destination information for terminal devices 7-9 to base stations 2, 4, and 6 to which terminal devices 7-9 are respectively connected.

[0101] The control means 12 generates a scanning schedule by a method described later and outputs the generated scanning schedule to the communication means 11.

[0102] Furthermore, when the control means 12 receives the measurement result MR_k from the communication means 11, it stores the received measurement result MR_k in the database 13 for all measurement results MR_2 to MR_6. The control means 12 then aggregates the measurement results MS_2 to MS_6 stored in the database 13 and performs a connection determination based on the aggregated results using the method described later.

[0103] Then, the control means 12 generates connection destination information (consisting of connection destination information for the base station and connection destination information for the terminal device) based on the result of the connection determination, and outputs the generated connection destination information (consisting of connection destination information for the base station and connection destination information for the terminal device) to the communication means 11.

[0104] Database 13 stores connection information [base station 2-terminal device 7], connection information [base station 4-terminal device 8], connection information [base station 6-terminal device 9], and measurement results MR_1~MR_6, associated with the time when the connection information [base station 2-terminal device 7], connection information [base station 4-terminal device 8], and connection information [base station 6-terminal device 9] were received.

[0105] [Description of the control device 1 in the communication system 10B] The communication means 11 receives the scan schedule from the control means 12 and transmits the received scan schedule to the base stations 2 and 3 via the backhaul line BHC.

[0106] Furthermore, the communication means 11 outputs the measurement result MR_7 of terminal device 7 and the measurement result MR_8 of terminal device 8 received by base station 2 via backhaul line BHC to control means 12, and outputs the measurement result MR_9 of terminal device 9 received by base station 3 to control means 12.

[0107] Furthermore, the communication means 11 receives connection destination information (consisting of connection destination information for base stations and connection destination information for terminal devices) from the control means 12, and transmits the received connection destination information (consisting of connection destination information for base stations and connection destination information for terminal devices) to base stations 2 and 3 via the backhaul line BHC.

[0108] The control means 12 generates a scanning schedule by a method described later and outputs the generated scanning schedule to the communication means 11.

[0109] Furthermore, when the control means 12 receives measurement result MR_7 from the communication means 11, it stores the received measurement result MR_7 in the database 13; when it receives measurement result MR_8 from the communication means 11, it stores the received measurement result MR_8 in the database 13; and when it receives measurement result MR_9 from the communication means 11, it stores the received measurement result MR_9 in the database 13. The control means 12 then aggregates the measurement results MS_7, MS_8, and MS_9 stored in the database 13 and performs a connection determination based on the aggregated results using a method described later.

[0110] Then, the control means 12 generates connection destination information (consisting of connection destination information for the base station and connection destination information for the terminal device) based on the result of the connection determination, and outputs the generated connection destination information (consisting of connection destination information for the base station and connection destination information for the terminal device) to the communication means 11.

[0111] [Description of the control device 1 in the communication system 10C] The communication means 11 receives the scan schedule from the control means 12 and transmits the received scan schedule to base stations 2-4 via the backhaul line BHC.

[0112] Furthermore, when the communication means 11 receives the measurement result MR_k from base station k (k is 2 to 4) via the backhaul line BHC, it outputs the received measurement result MR_k to the control means 12 for all measurement results MR_2 to MR_4 transmitted from base stations 2 to 4.

[0113] Furthermore, the communication means 11 receives connection destination information (consisting of connection destination information for base stations and connection destination information for terminal devices) from the control means 12, transmits the received connection destination information for base stations 2-4 to base stations 2-4 via the backhaul line BHC, and transmits the connection destination information for terminal devices 7-9 to base stations 2-4 to which terminal devices 7-9 are respectively connected.

[0114] The control means 12 generates a scanning schedule by a method described later and outputs the generated scanning schedule to the communication means 11.

[0115] Furthermore, when the control means 12 receives the measurement result MR_k from the communication means 11, it stores the received measurement result MR_k in the database 13 for all measurement results MR_2 to MR_4. The control means 12 then aggregates the measurement results MS_2 to MS_4 stored in the database 13 and performs a connection determination based on the aggregated results using the method described later.

[0116] Then, the control means 12 generates connection destination information (consisting of connection destination information for the base station and connection destination information for the terminal device) based on the result of the connection determination, and outputs the generated connection destination information (consisting of connection destination information for the base station and connection destination information for the terminal device) to the communication means 11.

[0117] Database 13 stores connection information [base station 2-terminal device 7], connection information [base station 3-terminal device 8], connection information [base station 4-terminal device 9], and measurement results MR_2~MR_4, associated with the time when the connection information [base station 2-terminal device 7], connection information [base station 3-terminal device 8], and connection information [base station 4-terminal device 9] were received.

[0118] In this embodiment of the invention, the communication systems 10A, 10B, and 10C described above constitute the communication system 10 according to this embodiment of the invention.

[0119] Therefore, in the communication system 10, there are cases where the number of base stations m is greater than or equal to the number of terminal devices n (see Figures 1 and 3), and cases where the number of base stations m is less than the number of terminal devices n (see Figure 2).

[0120] In the communication system 10, n terminal devices are connected to some or all of the m base stations.

[0121] Figure 5 is a schematic diagram of the base station 2 shown in Figures 1 to 3. Referring to Figure 5, the base station 2 comprises antennas 21A, 22A, and 23A, beamforming means 21 to 23, wireless communication means 24, measuring means 25, control means 26, and communication means 27.

[0122] Antenna 21A is an antenna for forming a beam in the microwave band (300 MHz to 300 GHz) and transmitting and receiving frames, and consists of one or more antennas.

[0123] Antenna 22A is an antenna that forms a beam in the millimeter-wave band (30 GHz to 300 GHz) and transmits and receives frames, and consists of multiple antennas.

[0124] Antenna 23A is an antenna that forms a beam in the terahertz wave band (100 GHz to 10 THz) and transmits and receives frames, and consists of multiple antennas.

[0125] Antenna 21A is connected to beamforming means 21. Antenna 22A is connected to beamforming means 22. Antenna 23A is connected to beamforming means 23.

[0126] When the beamforming means 21 receives an instruction signal S_MC_B for forming a beam in the microwave band from the wireless communication means 24, it controls the antenna 21A to form a beam in the microwave band by analog beamforming or digital beamforming, or without forming a beam.

[0127] When the beamforming means 22 receives beam numbers "1" to "x" in the millimeter-wave band from the wireless communication means 24, it uses analog beamforming or digital beamforming to form multiple beams b1 to b in the millimeter-wave band. x The antenna 22A is controlled to sequentially form the shapes shown.

[0128] When the beamforming means 23 receives beam numbers "1" to "x" in the terahertz wave band from the wireless communication means 24, it uses analog beamforming or digital beamforming to form multiple beams b1 to b in the terahertz wave band. x The antenna 23A is controlled to sequentially form the shapes shown.

[0129] When the wireless communication means 24 receives only the scanning schedule from the control means 26, it controls the beam of the antenna 23A to multiple beams b1~b during each scanning period of the scanning schedule. x The beam numbers "1" to "x" for sequential switching are output to the beamforming means 23.

[0130] Furthermore, the wireless communication means 24 transmits the scanning schedule and frames F1 to F, each containing beam numbers "1" to "x". x When the control means 26 receives the signal, in one scanning period, beam b of beam number k k Using frame F k Control the beamforming means 23 to perform the transmission of over the entire scanning period.

[0131] Furthermore, when the antenna 23A receives a signal through the beam formed by the beamforming means 23, the wireless communication means 24 receives the received signal from the antenna 23A and the beam number k of the beam at the time the received signal was received from the beamforming means 23, and outputs the received signal and beam number k to the measuring means 25.

[0132] Furthermore, when the wireless communication means 24 receives a measurement result [beam number k / received signal strength RSSI] from a terminal device (any of terminal devices 7 to 9) via the antenna 21A, it outputs the received measurement result [beam number k / received signal strength RSSI] to the control means 26.

[0133] Furthermore, when the wireless communication means 24 receives a frame F_AP from the control means 26, which includes the destination of the connection information (= a terminal device connected to the base station 2) and the connection information (= connection information for the terminal device), it outputs the instruction signal S_MC_B and frame F_AP to the beamforming means 21, and controls the beamforming means 21 to transmit frame F_A to the destination (= a terminal device connected to the base station 2) using a microwave beam.

[0134] When the measurement means 25 receives a received signal and beam number k from the wireless communication means 24, it detects the received signal intensity RSSI of the received signal. The measurement means 25 then generates a measurement result [beam number k / received signal intensity RSSI] which associates the beam number k with the received signal intensity RSSI, and outputs the generated measurement result [beam number k / received signal intensity RSSI] to the control means 26.

[0135] When the control means 26 receives a scanning schedule from the communication means 27, it refers to the received scanning schedule and determines whether or not the base station 2 will receive the beam.

[0136] In this case, when the control means 26 determines that the base station 2 has received a beam, it waits for the measurement result [beam number k / received signal strength RSSI] from the measurement means 25.

[0137] Then, when the control means 26 receives the measurement result [beam number k / received signal strength RSSI] from the measurement means 25, it outputs the received measurement result [beam number k / received signal strength RSSI] to the communication means 27.

[0138] On the other hand, when the control means 26 determines that the base station 2 does not receive a beam (i.e., when it determines that the base station 2 transmits multiple beams sequentially), it controls frames F1 to F containing beam numbers "1" to "x" respectively. x Generates the scanning schedule and frames F1~F x The output is sent to the wireless communication means 24.

[0139] Furthermore, when the control means 26 receives connection destination information (consisting of connection destination information for the base station and connection destination information for the terminal device) from the communication means 27, it outputs the received connection destination information for the terminal device to the wireless communication means 24.

[0140] When the communication means 27 receives the measurement result [beam number k / received signal strength RSSI] from the control means 26, it transmits the received measurement result [beam number k / received signal strength RSSI] to the control device 1 via the backhaul line BHC.

[0141] Furthermore, the communication means 27 receives the scanning schedule from the control device 1 via the backhaul line BHC and outputs the received scanning schedule to the control means 26.

[0142] Furthermore, the communication means 27 receives connection destination information (consisting of connection destination information for the base station and connection destination information for the terminal device) from the control device 1 via the backhaul line BHC, and outputs the received connection destination information for the terminal device to the control means 26.

[0143] As described above, base station 2 has the capability to perform wireless communication in the microwave, millimeter wave, and terahertz wave bands.

[0144] Each of base stations 3 through 6 has the same configuration as base station 2 shown in Figure 5.

[0145] Figure 6 is a schematic diagram of the terminal device 7 shown in FIGS. 1 to 3. Referring to FIG. 7, the terminal device 7 includes antennas 71A, 72A, 73A, beamforming means 71 to 73, wireless communication means 74, measurement means 75, and control means 76.

[0146] Antenna 71A is an antenna for forming a beam in the microwave band (300 MHz to 300 GHz) and transmitting and receiving frames, and is composed of one or more antennas.

[0147] Antenna 72A is an antenna for forming a beam in the millimeter wave band (30 GHz to 300 GHz) and transmitting and receiving frames, and is composed of a plurality of antennas.

[0148] Antenna 73A is an antenna for forming a beam in the terahertz wave band (100 GHz to 10 THz) and transmitting and receiving frames, and is composed of a plurality of antennas.

[0149] Antenna 71A is connected to beamforming means 71. Antenna 72A is connected to beamforming means 72. Antenna 73A is connected to beamforming means 73.

[0150] When beamforming means 71 receives an instruction signal S_MC_T for forming a beam in the microwave band from wireless communication means 74, it controls antenna 71A to form a beam in the microwave band.

[0151] When beamforming means 72 receives beam numbers "1" to "x" in the millimeter wave band from wireless communication means 74, it controls antenna 72A to sequentially form a plurality of beams b1 to b x by analog beamforming or digital beamforming.

[0152] When the beamforming means 73 receives beam numbers "1" to "x" in the terahertz wave band from the wireless communication means 74, it uses analog beamforming or digital beamforming to form multiple beams b1 to b in the terahertz wave band. x The antenna 73A is controlled to sequentially form the shapes shown.

[0153] When the wireless communication means 74 receives a scan schedule via the antenna 71A, it outputs the received scan schedule to the control means 76.

[0154] Furthermore, when the wireless communication means 74 receives the beam numbers "1" to "y" formed by the antenna 73A from the control means 76, it outputs the beam numbers "1" to "y" to the beamforming means 73, and beams b1 to b y The beamforming means 73 is controlled so that the antenna 73A forms a beam.

[0155] Furthermore, when the antenna 73A receives a signal through the beam formed by the beamforming means 73, the wireless communication means 74 receives the received signal from the antenna 73A and the beam number k of the beam at the time the received signal was received from the beamforming means 73, and outputs the received signal and beam number k to the measuring means 75.

[0156] Furthermore, when the wireless communication means 74 receives the measurement result [beam number k / received signal strength RSSI] from the control means 76, it controls the beamforming means 71 to transmit the received measurement result [beam number k / received signal strength RSSI] to the base station to which the terminal device 7 is connected via the antenna 71A.

[0157] Furthermore, when the wireless communication means 74 receives connection destination information (= connection destination information for terminal devices) via the antenna 71A, it outputs the received connection destination information (= connection destination information for terminal devices) to the control means 76.

[0158] When the measuring means 75 receives a received signal and beam number k from the wireless communication means 74, it detects the received signal intensity RSSI of the received signal. The measuring means 75 then outputs the beam number k and the received signal intensity RSSI to the control means 76.

[0159] When the control means 76 receives the beam number k and the received signal strength RSSI from the measurement means 75, it generates a measurement result [beam number k / received signal strength RSSI] including the beam number k and the received signal strength RSSI, outputs the generated measurement result [beam number k / received signal strength RSSI] to the wireless communication means 74, and controls the wireless communication means 74 to transmit the measurement result [beam number k / received signal strength RSSI] to the base station to which the terminal device 7 is connected.

[0160] Furthermore, the control means 76 receives connection destination information (= connection destination information for terminal devices) from the wireless communication means 74. The control means 76 then refers to the connection destination information (= connection destination information for terminal devices) to obtain the connection destination of terminal device 7.

[0161] As described above, terminal device 7 has the function of performing wireless communication in the microwave band, millimeter wave band, and terahertz wave band.

[0162] Each of the terminal devices 8 and 9 has the same configuration as terminal device 7 shown in Figure 6.

[0163] Figure 7 is a conceptual diagram of frame F. Referring to Figure 7, frame F includes the source ID, source beam number, TTL (Time To Live), and "End".

[0164] The Source ID is the identification information of the source of frame F. The Source Beam Number is the number of the beam transmitted from the source. TTL represents the validity period of frame F. "End" indicates the end of frame F.

[0165] Frame F does not contain destination identification information because it is obvious from the scanning schedule described later.

[0166] In the following, it will be explained that base stations 2-6 and terminal devices 7-9 use terahertz beams to transmit and receive frames to acquire measurement results used for determining the connection between base stations 2-6 and terminal devices 7-9, and that control device 1 makes the connection determination between base stations 2-6 and terminal devices 7-9 based on the measurement results acquired by base stations 2-6 and terminal devices 7-9.

[0167] Therefore, in the following, when "beam" is used, "beam" refers to a beam in the terahertz wave band.

[0168] Figure 8 is a conceptual diagram of the beam formed by terminal device 7. Refer to Figure 8, beams b1~b 24 This represents a beam in the planar direction. Beams b1~b 24 Each of these is a beam with a half-angle of 5 to 10 degrees when the peak gain drops by 3 dB. And beams b1 to b 24 For example, two adjacent beam b k ,b k+1 This is a beam when its direction forms an angle of 15 degrees.

[0169] The beamforming means 73 of the terminal device 7 uses analog beamforming or digital beamforming to form two adjacent beams b k ,b k+1 By controlling antenna 73A so that the direction forms a 15-degree angle, beams b1, b2, b3, ..., b are produced from antenna 73A. 24 These are formed sequentially.

[0170] Each of the base stations 2-6 and terminal devices 8 and 9 also uses beams b1, b2, b3, ..., b in the same manner as terminal device 7. 24 These are formed sequentially.

[0171] Figure 9 is a conceptual diagram showing the beam scanning by the source and destination during the scanning period.

[0172] Referring to Figure 9, base station 2 is the source and terminal device 7 is the destination. During one scanning period, base station 2 transmits frame F using beam b1, and terminal device 7 transmits beams b1 to b 24 Form them sequentially (i.e., beam b1~b 24 (Scan the beam) and receive beam b1.

[0173] Subsequently, base station 2 transmits frame F using beam b2, and terminal device 7 uses beams b1~b 24 Form them sequentially (i.e., beam b1~b 24 (Scan the beam) and receive beam b2.

[0174] Similarly, base station 2 uses beam b 24 Using this method, frame F is transmitted, and terminal device 7 uses beams b1~b 24 Form them sequentially (i.e., beam b1~b 24 (Scanning) beam b 24 Receive.

[0175] Then, the terminal device 7 detects the received signal strength RSSI when it receives frame F transmitted from base station 2, and also detects the beam number k included in frame F. The terminal device 7 then creates a measurement result [beam number k / received signal strength RSSI] that associates beam number k with the received signal strength RSSI.

[0176] Similarly, when terminal device 7 is the source and base station 2 is the destination, terminal device 7 transmits frame F using beam b1, and base station 2 transmits beams b1~b 24 Form them sequentially (i.e., beam b1~b 24 (Scan the beam) and receive beam b1.

[0177] Subsequently, terminal device 7 transmits frame F using beam b2, and base station 2 transmits beams b1~b 24 Form them sequentially (i.e., beam b1~b 24 (Scan the beam) and receive beam b2.

[0178] Similarly, the terminal device 7 transmits the frame F using the beam b 24 and the base station 2 sequentially forms the beams b1 to b 24 (that is, scans the beams b1 to b 24 ) to receive the beam b 24 .

[0179] Then, when the base station 2 receives the frame F transmitted from the terminal device 7, the base station 2 detects the received signal strength RSSI and also detects the beam number k included in the frame F. Then, the base station 2 creates a measurement result [beam number k / received signal strength RSSI] associating the beam number k with the received signal strength RSSI.

[0180] Thus, in both the case where the terminal device 7 is the transmitter and the base station 2 is the receiver, and the case where the base station 2 is the transmitter and the terminal device 7 is the receiver, the base station 2 and the terminal device 7 cooperate to sequentially scan the beams from beam b1 to b 24 .

[0181] In the embodiment of the present invention, when the number m of m base stations is smaller than the number n of n terminal devices (that is, when m < n (see FIG. 2)), the m base stations are the transmitters and the n terminal devices are the receivers.

[0182] Then, when one of the m base stations transmits the frame F using one beam, (m - 1) of the m base stations enter the sleep state, and the n terminal devices synchronously scan the beams from beam b1 to b 24 to receive the frame F.

[0183] Also, in the embodiment of the present invention, when the number m of m base stations is greater than or equal to the number n of n terminal devices (that is, when m ≥ n (see FIGS. 1 and 3)), the n terminal devices are the transmitters and the m base stations are the receivers.

[0184] Here, when the number of base stations m is equal to the number of terminal devices n, the reason why n terminal devices become the source is as follows:

[0185] This is because, when the number of base stations m is equal to the number of terminal devices n, if m base stations act as transmitters, the process of transmitting beam scanning measurement results from terminal devices to base stations becomes redundant.

[0186] Furthermore, when the number of base stations m is greater than or equal to the number of terminal devices n, and one of the n terminal devices that are the source of the frame is transmitting frame F using one beam, then (n-1) of the n terminal devices enter a sleep state, and the m base stations synchronously transmit beams b1~b 24 The system scans sequentially and receives frame F.

[0187] Figure 10 is a conceptual diagram showing the source and destination beam scanning during one scanning period. In Figure 10, the terminal device STA is the source, and the two base stations AP1 and AP2 are the destinations.

[0188] Referring to Figure 10, when terminal device STA transmits a frame using one beam 1, the two base stations AP1 and AP2 synchronously receive the frame transmitted using beam 1 of terminal device STA, sequentially switching beams from beam 1 to beam x (see (1) in Figure 10).

[0189] After (1), when terminal device STA transmits a frame using one beam 2, the two base stations AP1 and AP2 synchronously switch beams sequentially from beam 1 to beam x and receive the frame transmitted using beam 2 of terminal device STA (see (2) in Figure 10).

[0190] (2) After this, for each of the beams 3 to y of the terminal device STA, the two base stations AP1 and AP2 synchronously switch beams sequentially from beam 1 to beam x, and sequentially receive frames transmitted using beam j of the terminal device STA for all of j=3 to y (see (3) in Figure 10).

[0191] In this way, by receiving a frame transmitted using one beam j of terminal device STA by synchronizing the reception of two base stations AP1 and AP2, frames transmitted using each of the y beams 1 to y of terminal device STA can be received by synchronizing the beams of multiple base stations AP1 and AP2 to x beams 1 to x, a number of times equal to [number of beams of base station AP × number of terminal device STA × number of beams of terminal device STA].

[0192] Therefore, frames transmitted using each of the y beams 1 to y of the terminal device STA can be received by synchronously switching the beams of multiple base stations AP1 and AP2 to x beams 1 to x, in fewer steps than in the conventional method (=[number of base stations × number of beams per base station × number of terminals × number of beams per terminal]).

[0193] In other words, the number of operations can be reduced by [(number of APs - 1) × number of terminal devices STA × number of beams of base station APs × number of beams of terminal devices STA] compared to the conventional method.

[0194] Figure 11 is another conceptual diagram showing the source and destination beam scanning during one scanning period. In Figure 11, the base station AP is the source, and the two terminal devices STA1 and STA2 are the destinations.

[0195] Referring to Figure 11, when base station AP1 transmits a frame using one beam 1, the two terminal devices STA1 and STA2 synchronously receive the frame transmitted using beam 1 of base station AP1, sequentially switching the beam from beam 1 to beam y (see (1) in Figure 11).

[0196] After (1), when base station AP1 transmits a frame using one beam 2, the two terminal devices STA1 and STA2 synchronously switch beams sequentially from beam 1 to beam y to receive the frame transmitted by base station AP1 using beam 2 (see (2) in Figure 11).

[0197] (2) After (2), for each of the beams 3 to x emitted by base station AP1, the two terminal devices STA1 and STA2 synchronously switch beams sequentially from beam 1 to beam y, and sequentially receive the frames transmitted using beam k of base station AP1 for all of k=3 to x (see (3) in Figure 11).

[0198] In this way, by synchronously receiving one beam k (where k is one of 1 to x) emitted from base station AP1 with two receiving terminal devices STA1 and STA2, frames transmitted using each of the x beams 1 to x of base station AP1 can be received by synchronously switching the beams of multiple terminal devices STA1 and STA2 to y beams 1 to y a number of times equal to [number of beams of base station AP × number of base station APs × number of beams of terminal device STA].

[0199] Therefore, frames transmitted using each of the x beams 1 to x of base station AP1 can be received by synchronously switching the beams of multiple terminal devices STA1 and STA2 to y beams 1 to y, in fewer steps (=[number of base stations × number of beams per base station × number of terminals × number of beams per terminal]) than in the conventional method (=[number of base stations × number of beams per base station × number of terminals]).

[0200] In other words, the number of operations can be reduced by [(number of terminal devices STA - 1) × number of base station APs × number of beams per base station AP × number of beams per terminal device STA] compared to the conventional method.

[0201] FIG. 12 is a schematic diagram showing a sequence when scanning a beam. In FIG. 12, it is assumed that the terminal device STA1 is connected to the base station AP1, the terminal device STA2 is connected to the base station AP2, and the terminal device STAn is connected to the base station APm. That is, it is assumed that all the terminal devices STA1, STA, STAn are connected to the base station AP. Also, the terminal device STA1 is the target for connection determination.

[0202] Referring to FIG. 12, when a scheduling period occurs, the control device 1 determines whether to create a scanning schedule. More specifically, the control device 1 determines whether to create a scanning schedule by determining whether a new terminal device has entered the communication system 10.

[0203] In this case, when the control device 1 determines that a new terminal device has entered the communication system, it determines to create a scanning schedule, and when it determines that a new terminal device has not entered the communication system 10, it determines not to create a scanning schedule.

[0204] This article is an English translation of the original Japanese text. The copyright of the original text belongs to the original author. And when the control device 1 determines to create a scanning schedule, it discriminates the scanning method (step S1).

[0205] More specifically, when the number m of base stations AP is smaller than the number n of terminal devices STA (that is, when m < n), the control device 1 discriminates that the base station AP transmits a frame with a beam and the n terminal devices STA receive the frame with a beam. This scanning method is called the "scanning method in the downlink".

[0206] On the other hand, when the number m of base stations AP is greater than or equal to the number n of terminal devices STA (that is, when m ≧ n), the control device 1 discriminates that the terminal device STA transmits a frame with a beam and the m base stations receive the frame with a beam. This scanning method is called the "scanning method in the uplink".

[0207] When the control device 1 determines the scanning method, it creates a scanning schedule according to the determined scanning method and transmits the created scanning schedule to all base stations AP1, AP2, and APm using the backhaul line BHC (steps S2, S3, S4).

[0208] When base station AP1 receives a scan schedule via the backhaul line BHC, it transmits the received scan schedule to the terminal device STA1 connected to it (step S5).

[0209] Furthermore, when base station AP2 receives a scan schedule via the backhaul line BHC, it transmits the received scan schedule to terminal device STA2 connected to it (step S6).

[0210] Furthermore, when the base station APm receives a scan schedule via the backhaul circuit BHC, it transmits the received scan schedule to the terminal device STAm connected to it (step S7).

[0211] Subsequently, beam scanning measurements are performed using the method described in Figure 10 or the method described in Figure 11 (step S8).

[0212] Then, once the beam scanning measurements are complete, base stations AP1, AP2, and APm transmit the measurement results to control device 1 using the backhaul line BHC.

[0213] When the control device 1 receives the measurement result via the backhaul line BHC, it performs a connection determination using the method described later (step S9).

[0214] Then, once the control device 1 has completed the connection determination, it creates connection destination information. The connection destination information consists of connection destination information for terminal devices and connection destination information for base stations. The connection destination information for terminal devices consists of the correspondence between terminal device STA and beam number, and the connection destination information for base stations consists of the correspondence between base station AP and beam number.

[0215] When the control device 1 creates connection destination information, it transmits the created connection destination information to base stations AP1 and AP2 using the backhaul line BHC (steps S10, S11).

[0216] When base station AP1 receives destination information via the backhaul line BHC, it transmits the received destination information to terminal device STA1 connected to it (step S12).

[0217] Then, base station AP1 switches beams based on the connection destination information (step S13), base station AP2 switches beams based on the connection destination information (step S14), and terminal device STA1 switches beams based on the connection destination information (step S15).

[0218] Here, base station AP2, which is not connected to terminal device STA1, also switches its beam because base stations AP1 and AP2 work together to communicate with terminal device STA1.

[0219] After step S15, base stations AP1 and AP2 work together to communicate data with terminal device STA1 in the terahertz band (step S16).

[0220] Figure 13 is a conceptual diagram of the beam scanning sequence when the terminal device is the source of transmission.

[0221] Referring to Figure 13, with terminal devices STA2 and STAn set to sleep mode, terminal device STA1 sequentially transmits frames using transmit beam 1, transmit beam 2, ..., transmit beam y.

[0222] Then, when terminal device STA1 is transmitting a frame with transmit beam 1, base stations AP1, AP2, and APm synchronously switch sequentially to receive beam 1, receive beam 2, ..., receive beam x, and receive the frame transmitted using terminal device STA1's transmit beam 1 with receive beams 1 through x.

[0223] Furthermore, when terminal device STA1 transmits a frame using transmit beam 2, base stations AP1, AP2, and APm synchronously switch their beams sequentially to receive beam 1, receive beam 2, ..., receive beam x, and receive the frame transmitted by terminal device STA1 using transmit beam 2 with receive beam 1 to receive beam x.

[0224] Similarly, when terminal device STA1 transmits a frame using transmit beam y, base stations AP1, AP2, and APm synchronously switch their beams sequentially to receive beam 1, receive beam 2, ..., receive beam x, and receive the frame transmitted by terminal device STA1 using transmit beam y with receive beam 1 to receive beam x.

[0225] In this way, base stations AP1, AP2, and APm synchronously scan the receiving beam from receiving beam 1 to receiving beam x while receiving each of the frames transmitted using the transmitting beam 1 to transmitting beam y of terminal device STA1.

[0226] When base station AP1 receives a frame transmitted from terminal device STA1, it detects the beam number y based on the received signal strength RSSI at the time of frame reception and the frame transmitted from terminal device STA1.

[0227] Then, base station AP1 creates a measurement result [beam number y / received signal strength RSSI] that associates beam number y with received signal strength RSSI, and transmits the created measurement result [beam number y / received signal strength RSSI] to control device 1 using backhaul line BHC.

[0228] Furthermore, base station AP2, in the same manner as base station AP1, creates the measurement result [beam number y / received signal strength RSSI] and transmits the created measurement result [beam number y / received signal strength RSSI] to control device 1 using the backhaul line BHC.

[0229] Furthermore, base station APm, in the same manner as base station AP1, creates the measurement result [beam number y / received signal strength RSSI] and transmits the created measurement result [beam number y / received signal strength RSSI] to control device 1 using the backhaul line BHC.

[0230] In Figure 13, when terminal devices STA2 and STAn are set to sleep mode, terminal device STA1 sequentially transmits frames using transmit beam 1, transmit beam 2, ..., transmit beam y because if terminal devices STA2 and STAn are not in sleep mode, the frames transmitted using transmit beam 1, transmit beam 2, ..., transmit beam y will interfere with the radio waves transmitted from terminal devices STA2 and STAn, and base stations AP1, AP2, and APm will not be able to accurately receive the frames transmitted from terminal device STA1 using transmit beam 1, transmit beam 2, ..., transmit beam y.

[0231] Furthermore, even if one of the base stations AP1, AP2, and APm is not connected to the terminal device, as described above, base stations AP1, AP2, and APm will synchronously receive frames transmitted using each of the transmit beams 1 to y of the terminal device STA1 by scanning them with the receive beam 1 to x.

[0232] As a result, even for base stations not connected to terminal devices, the control device 1 creates connection destination information based on the measurement results, so base stations not connected to terminal devices can be considered as candidates for handover.

[0233] Figures 14 and 15 are the first and second conceptual diagrams of the beam scanning sequence when the base station is the source, respectively.

[0234] Referring to Figure 14, with base stations AP2 and APm set to sleep state, base station AP1 sequentially transmits frames using transmit beam 1, transmit beam 2, ..., transmit beam x.

[0235] When the base station AP1 is transmitting a frame using transmission beam 1, the terminal devices STA1, STA2, …, STAn synchronously switch to receive beams 1, receive beam 2, …, receive beam y in sequence to receive the frame transmitted using transmission beam 1 of the base station AP1 with receive beams 1 to receive beam y.

[0236] Also, when the base station AP1 is transmitting a frame using transmission beam 2, the terminal devices STA1, STA2, …, STAn synchronously switch to receive beams 1, receive beam 2, …, receive beam y in sequence to receive the frame transmitted using transmission beam 2 of the base station AP1 with receive beams 1 to receive beam y.

[0237] Hereinafter, in the same manner, when the base station AP1 is transmitting a frame using transmission beam x, the terminal devices STA1, STA2, …, STAn synchronously switch to receive beams 1, receive beam 2, …, receive beam y in sequence to receive the frame transmitted using transmission beam x of the base station AP1 with receive beams 1 to receive beam y.

[0238] Subsequently, in a state where the base stations AP1, APm are set to the sleep state, the base station AP2 sequentially transmits frames using transmission beam 1, transmission beam 2, …, transmission beam x.

[0239] When the base station AP2 is transmitting a frame using transmission beam 1, the terminal devices STA1, STA2, …, STAn synchronously switch to receive beams 1, receive beam 2, …, receive beam y in sequence to receive the frame transmitted using transmission beam 1 of the base station AP2 with receive beams 1 to receive beam y.

[0240] Also, when the base station AP2 is transmitting a frame using transmission beam 2, the terminal devices STA1, STA2, …, STAn synchronously switch to receive beams 1, receive beam 2, …, receive beam y in sequence to receive the frame transmitted using transmission beam 2 of the base station AP2 with receive beams 1 to receive beam y.

[0241] Similarly, when base station AP2 transmits a frame using transmit beam x, terminal devices STA1, STA2, and STAn synchronously switch sequentially to receive beam 1, receive beam 2, ..., receive beam y, and receive the frame transmitted by base station AP2 using transmit beam x with receive beam 1 to receive beam y.

[0242] Referring to Figure 15, with base stations AP1 and AP2 set to sleep mode, base station APm sequentially transmits frames using transmit beam 1, transmit beam 2, ..., transmit beam x.

[0243] Then, when the base station APm transmits a frame using transmit beam 1, the terminal devices STA1, STA2, and STAn synchronously switch sequentially to receive beam 1, receive beam 2, ..., receive beam y, and receive the frame transmitted by base station APm using transmit beam 1 with receive beams 1 through y.

[0244] Furthermore, when the base station APm transmits a frame using transmit beam 2, terminal devices STA1, STA2, and STAn synchronously switch sequentially to receive beam 1, receive beam 2, ..., receive beam y, and receive the frame transmitted by base station APm using transmit beam 2 with receive beam 1 to receive beam y.

[0245] Similarly, when the base station APm transmits a frame using the transmit beam x, terminal devices STA1, STA2, and STAn synchronously switch sequentially to receive beam 1, receive beam 2, ..., receive beam y to receive the frame transmitted by base station APm using the transmit beam x with receive beam 1 to receive beam y.

[0246] When terminal device STA1 receives a frame transmitted from base station AP1, it detects the received signal strength RSSI_AP1 at the time of frame reception and the beam number x_AP1 based on the frame transmitted from base station AP1.

[0247] Then, terminal device STA1 creates a measurement result [beam number y_AP1 / received signal strength RSSI_AP1]_STA1_1, which associates beam number y_AP1 with received signal strength RSSI_AP1.

[0248] Furthermore, when terminal device STA1 receives a frame transmitted from base station AP2, it detects the received signal strength RSSI_AP2 at the time of frame reception and the beam number x_AP2 based on the frame transmitted from base station AP2.

[0249] Then, terminal device STA1 creates a measurement result [beam number y_AP2 / received signal strength RSSI_AP2]_STA1_2, which associates beam number y_AP2 with received signal strength RSSI_AP2.

[0250] Similarly, when terminal device STA1 receives a frame transmitted from base station APm, it detects the received signal strength RSSI_APm at the time of frame reception and the beam number x_APm based on the frame transmitted from base station APm.

[0251] Then, terminal device STA1 creates a measurement result [beam number y_APm / received signal strength RSSI_APm]_STA1_m, which associates beam number y_APm with received signal strength RSSI_APm.

[0252] Furthermore, terminal device STA2 generates measurement results [beam number y_AP1 / received signal strength RSSI_AP1]_STA2_1 to [beam number y_APm / received signal strength RSSI_APm]_STA2_m in the same manner as terminal device STA1.

[0253] Similarly, terminal device STAn creates measurement results [beam number y_AP1 / received signal strength RSSI_AP1]_STAn_1 to [beam number y_APm / received signal strength RSSI_APm]_STAn_m in the same manner as terminal device STA1.

[0254] Then, terminal device STA1 transmits the measurement results [beam number y_AP1 / received signal strength RSSI_AP1]_STA1_1~[beam number y_APm / received signal strength RSSI_APm]_STA1_m to base station AP1 to which it is connected.

[0255] Furthermore, terminal device STA2 transmits the measurement results [beam number y_AP1 / received signal strength RSSI_AP1]_STA2_1 to [beam number y_APm / received signal strength RSSI_APm]_STA2_m to base station AP2 to which it is connected.

[0256] Similarly, the terminal device STAn transmits the measurement results [beam number y_AP1 / received signal strength RSSI_AP1]_STAn_1 to [beam number y_APm / received signal strength RSSI_APm]_STAn_m to the base station APm to which it is connected.

[0257] Then, when base station AP1 receives the measurement results [beam number y_AP1 / received signal strength RSSI_AP1]_STA1_1~[beam number y_APm / received signal strength RSSI_APm]_STA1_m from terminal device STA1, it transmits the received measurement results [beam number y_AP1 / received signal strength RSSI_AP1]_STA1_1~[beam number y_APm / received signal strength RSSI_APm]_STA1_m to control device 1 using backhaul line BHC.

[0258] Furthermore, when base station AP2 receives measurement results [beam number y_AP1 / received signal strength RSSI_AP1]_STA2_1~[beam number y_APm / received signal strength RSSI_APm]_STA2_m from terminal device STA2, it transmits the received measurement results [beam number y_AP1 / received signal strength RSSI_AP1]_STA2_1~[beam number y_APm / received signal strength RSSI_APm]_STA2_m to control device 1 using backhaul line BHC.

[0259] Similarly, when the base station APm receives the measurement results [beam number y_AP1 / received signal strength RSSI_AP1]_STAn_1 to [beam number y_APm / received signal strength RSSI_APm]_STAn_m from the terminal device STAn, it transmits the received measurement results [beam number y_AP1 / received signal strength RSSI_AP1]_STAn_1 to [beam number y_APm / received signal strength RSSI_APm]_STAn_m to the control device 1 using the backhaul line BHC.

[0260] In FIG. 14, when the base stations AP2 and APm are set to the sleep state, the reason why the base station AP1 sequentially transmits frames using transmission beams 1, transmission beam 2, ···, transmission beam x is that if the base stations AP2 and APm are not in the sleep state, the frames transmitted using transmission beams 1, transmission beam 2, ···, transmission beam x will interfere with the radio waves transmitted from the base stations AP2 and APm, and the terminal devices STA1, STA2, ···, STAn cannot accurately receive the frames transmitted using the transmission beams 1, transmission beam 2, ···, transmission beam x of the base station AP1.

[0261] Also, in FIG. 14, when the base stations AP1 and APm are set to the sleep state, the reason why the base station AP2 sequentially transmits frames using transmission beams 1, transmission beam 2, ···, transmission beam x is that if the base stations AP1 and APm are not in the sleep state, the frames transmitted using transmission beams 1, transmission beam 2, ···, transmission beam x will interfere with the radio waves transmitted from the base stations AP1 and APm, and the terminal devices STA1, STA2, ···, STAn cannot accurately receive the frames transmitted using the transmission beams 1, transmission beam 2, ···, transmission beam x transmitted from the base station AP2.

[0262] Furthermore, in Figure 15, when base stations AP1 and AP2 are set to sleep mode, base station APm sequentially transmits frames using transmit beam 1, transmit beam 2, ..., transmit beam x because if base stations AP1 and AP2 are not in sleep mode, the frames transmitted using transmit beam 1, transmit beam 2, ..., transmit beam x will interfere with the radio waves transmitted from base stations AP1 and AP2, and terminal devices STA1, STA2, and STAn will not be able to accurately receive the frames transmitted from base station APm using transmit beam 1, transmit beam 2, ..., transmit beam x.

[0263] Figure 16 is a schematic diagram showing an example of a scanning schedule. Note that Figure 16 shows an example of a scanning schedule when the terminal device STA is the source (i.e., an example of a scanning schedule in uplink measurement).

[0264] Referring to Figure 16, each of the scanning periods TS1 to TS5 represents a start time using a time slot. It is assumed that all base station APs and terminal devices STAs are time-synchronized via a pre-established link.

[0265] Note that a time slot may represent not only the start time, but also "start time + end time" or "start time + duration".

[0266] Furthermore, each of the scanning periods TS1 to TS4 consists of, for example, four sub-scanning periods. That is, scanning period TS1 consists of four sub-scanning periods TS1_1 to TS1_4, scanning period TS2 consists of four sub-scanning periods TS2_1 to TS2_4, scanning period TS3 consists of four sub-scanning periods TS3_1 to TS3_4, and scanning period TS4 consists of four sub-scanning periods TS4_1 to TS4_4.

[0267] Furthermore, the length of the scan period and sub-scan periods are variable, and the minimum time per sub-scan period is set to, for example, the length required to transmit an LLDP (Link Layer Discovery Protocol) frame (see Figure 7).

[0268] The scanning schedule includes, during scanning period TS1, terminal device STA1 forming beam 1 and transmitting a frame, STA2 and STAn entering a sleep state, and base stations AP1, AP2, and APm synchronously scanning the beam to beams 1-4 while receiving frames from terminal device STA1.

[0269] The scanning period TS1 consists of four sub-scanning periods TS1_1 to TS1_4. Sub-scanning period TS1_1 includes base stations AP1, AP2, and APm synchronously receiving frames transmitted using beam 1 of terminal device STA1 with beam 1; sub-scanning period TS1_2 includes base stations AP1, AP2, and APm synchronously receiving frames transmitted using beam 1 of terminal device STA1 with beam 2; sub-scanning period TS1_3 includes base stations AP1, AP2, and APm synchronously receiving frames transmitted from terminal device STA1 using beam 1 with beam 3; and sub-scanning period TS1_4 includes base stations AP1, AP2, and APm synchronously receiving frames transmitted from terminal device STA1 using beam 1 with beam 4.

[0270] Furthermore, the scanning schedule includes, during scanning period TS2, terminal device STA1 transmitting a frame using beam 2, STA2 and STAn entering a sleep state, and base stations AP1, AP2, and APm synchronously scanning beams 1 to 4 while receiving frames from terminal device STA1 using beams 1 to 4.

[0271] Furthermore, the scanning schedule includes, during scanning period TS3, terminal device STA1 transmitting a frame using beam 3, STA2 and STAn entering a sleep state, and base stations AP1, AP2, and APm synchronously scanning beams 1 to 4 while receiving frames from terminal device STA1 using beams 1 to 4.

[0272] Furthermore, the scanning schedule includes, during the scanning period TS4, terminal device STA1 transmitting a frame using beam 4, STA2 and STAn entering a sleep state, and base stations AP1, AP2, and APm synchronously scanning beams 1 to 4 while receiving frames from terminal device STA1 using beams 1 to 4.

[0273] Furthermore, the scanning schedule includes the following: during the scanning period TS5, terminal device STA1 will not operate, terminal devices STA2 and STAn will enter a sleep state, and base stations AP1, AP2, and APm will each transmit measurement results.

[0274] Therefore, the scanning period TS5 includes each of the base stations AP1, AP2, and APm creating measurement results using the method described above and transmitting the created measurement results to the control device 1 using the backhaul line BHC.

[0275] Note that, similar to scanning period TS1, scanning periods TS2 to TS4 include sub-scanning periods TS2_1 to TS2_4, sub-scanning periods TS3_1 to TS3_4, and sub-scanning periods TS4_1 to TS4_4, respectively.

[0276] Sub-scan period TS2_1 includes base stations AP1, AP2, and APm synchronously receiving frames transmitted using beam 2 of terminal device STA1 with beam 1; sub-scan period TS2_2 includes base stations AP1, AP2, and APm synchronously receiving beam 2 from terminal device STA1 with beam 2; sub-scan period TS2_3 includes base stations AP1, AP2, and APm synchronously receiving frames transmitted using beam 2 of terminal device STA1 with beam 3; and sub-scan period TS2_4 includes base stations AP1, AP2, and APm synchronously receiving frames transmitted using beam 2 of terminal device STA1 with beam 4.

[0277] Furthermore, sub-scanning period TS3_1 includes base stations AP1, AP2, and APm synchronously receiving frames transmitted using beam 3 of terminal device STA1 with beam 1; sub-scanning period TS3_2 includes base stations AP1, AP2, and APm synchronously receiving beam 3 from terminal device STA1 with beam 2; sub-scanning period TS3_3 includes base stations AP1, AP2, and APm synchronously receiving frames transmitted using beam 3 of terminal device STA1 with beam 3; and sub-scanning period TS3_4 includes base stations AP1, AP2, and APm synchronously receiving frames transmitted using beam 3 of terminal device STA1 with beam 4.

[0278] Furthermore, sub-scanning period TS4_1 includes base stations AP1, AP2, and APm synchronously receiving frames transmitted using beam 4 of terminal device STA1 with beam 1; sub-scanning period TS4_2 includes base stations AP1, AP2, and APm synchronously receiving frames transmitted using beam 4 of terminal device STA1 with beam 2; sub-scanning period TS3_3 includes base stations AP1, AP2, and APm synchronously receiving frames transmitted using beam 4 of terminal device STA1 with beam 3; and sub-scanning period TS3_4 includes base stations AP1, AP2, and APm synchronously receiving frames transmitted using beam 4 of terminal device STA1 with beam 4.

[0279] Figure 17 is a schematic diagram showing another example of a scan schedule. Note that Figure 17 shows an example of a scan schedule when the base station AP is the source (i.e., an example of a scan schedule in downlink measurement).

[0280] Referring to Figure 17, the scanning period TS1 to TS4 includes the following: with base stations AP2 and APm set to sleep state, base station AP1 transmits frames using beams 1 to 4, and terminal devices STA1, STA2, and STAn synchronously scan the beams from beams 1 to 4 to receive the frames transmitted by base station AP1 on each of beams 1 to 4.

[0281] Furthermore, the scanning period TS5 to TS8 includes the following: with base stations AP1 and APm set to sleep state, base station AP2 transmits frames using beams 1 to 4, and terminal devices STA1, STA2, and STAn synchronously scan the beams from beams 1 to 4 to receive the frames transmitted by base station AP2 on each of beams 1 to 4.

[0282] Furthermore, the scanning period TS9 to TS12 includes the following: with base stations AP1 and AP2 set to sleep state, base station APm transmits frames using beams 1 to 4, and terminal devices STA1, STA2, and STAn synchronously scan the beams from beams 1 to 4 to receive the frames transmitted by base station APm on each of beams 1 to 4.

[0283] The scanning period TS13 includes the terminal devices STA1, STA2, and STAn creating measurement results in the manner described above, transmitting the created measurement results to base stations AP1 (the base station to which terminal device STA1 is connected), AP2 (the base station to which terminal device STA2 is connected), and APm (the base station to which terminal device STAn is connected), respectively, and base stations AP1, AP2, and APm receiving the measurement results from terminal devices STA1, STA2, and STAn, respectively.

[0284] Furthermore, the scanning period TS14 includes the transmission of measurement results received by base stations AP1, AP2, and APm from terminal devices STA1, STA2, and STAn, respectively, to the control device 1 using the backhaul line BHC.

[0285] The scanning period TS1 consists of sub-scanning periods TS1_1 to TS1_4.

[0286] Sub-scan period TS1_1 includes terminal devices STA1, STA2, and STAn synchronously receiving beam 1 from base station AP1 with beam 1; sub-scan period TS1_2 includes terminal devices STA1, STA2, and STAn synchronously receiving beam 1 from base station AP1 with beam 2; sub-scan period TS1_3 includes terminal devices STA1, STA2, and STAn synchronously receiving beam 1 from base station AP1 with beam 3; and sub-scan period TS1_4 includes terminal devices STA1, STA2, and STAn synchronously receiving beam 1 from base station AP1 with beam 4.

[0287] Furthermore, the scanning period TS2 consists of sub-scanning periods TS2_1 to TS2_4.

[0288] Sub-scan period TS2_1 includes terminal devices STA1, STA2, and STAn synchronously receiving beam 2 from base station AP1 with beam 1; sub-scan period TS2_2 includes terminal devices STA1, STA2, and STAn synchronously receiving beam 2 from base station AP1 with beam 2; sub-scan period TS2_3 includes terminal devices STA1, STA2, and STAn synchronously receiving beam 2 from base station AP1 with beam 3; and sub-scan period TS2_4 includes terminal devices STA1, STA2, and STAn synchronously receiving beam 2 from base station AP1 with beam 4.

[0289] The same applies to the sub-scan periods of each of the scanning periods TS3 to TS4. In this case, for the sub-scan periods TS3_2 to TS3_4 of scanning period TS3, replace "beam 1 from base station AP1" with "beam 3 from base station AP1" in the explanation for the sub-scan periods TS1_2 to TS1_4 of scanning period TS1, and for the sub-scan periods TS4_2 to TS4_4 of scanning period TS4, replace "beam 1 from base station AP1" with "beam 4 from base station AP1" in the explanation for the sub-scan periods TS1_2 to TS1_4 of scanning period TS1.

[0290] The explanation for the sub-scanning periods TS5_1~TS5_4, TS6_1~TS6_4, TS7_1~TS7_4, TS8_1~TS8_4, TS9_1~TS9_4, TS10_1~TS10_4, TS11_1~TS11_4, TS12_1~TS12_4 in scanning periods TS5~TS12 is the same as the explanation for the sub-scanning periods TS1_1~TS1_4, TS2_1~TS2_4, TS3_1~TS3_4, TS4_1~TS4_4 in scanning periods TS1~TS4 described above.

[0291] Figure 18 is a schematic diagram showing the measurement results. Referring to Figure 18, measurement result MR_AP1 is the measurement result measured by base station AP1 on the uplink, measurement result MR_AP2 is the measurement result measured by base station AP2 on the uplink, and so on, with measurement result MR_APm being the measurement result measured by base station APm on the uplink.

[0292] In the measurement result MR_AP1, “AP Beam 1” to “AP Beam 4” in the row direction are beams 1 to 4 when base station AP1 receives frames transmitted by beams 1 to 4 of terminal devices STA1 to STAn, respectively.

[0293] Furthermore, in the measurement result MR_AP2, “AP Beam 1” to “AP Beam 4” in the row direction are beams 1 to 4 when base station AP2 receives frames transmitted by beams 1 to 4 of terminal devices STA1 to STAn, respectively.

[0294] Similarly, in the measurement result MR_APm, “AP Beam 1” to “AP Beam 4” in the row direction are beams 1 to 4 when base station APm receives frames transmitted by beams 1 to 4 of terminal devices STA1 to STAn, respectively.

[0295] In each of the measurement results MR_AP1 to MR_APm, “STA1 beam 1” to “STA1 beam 4” in the column direction are beams 1 to 4 used by terminal device STA1 to transmit frames, and similarly thereafter, “STAn beam 1” to “STAn beam 4” in the column direction are beams 1 to 4 used by terminal device STAn to transmit frames.

[0296] As a result, in the measurement result MR_AP1, the received signal strength RSSI of "-89dBm" corresponding to "AP beam 1" and "STA1 beam 1" is the received signal strength when base station AP1 receives a frame transmitted by terminal device STA1 using beam 1 when terminal device STA1 transmits a frame using beam 1, and the received signal strength RSSI of "-58dBm" corresponding to "AP beam 2" and "STA1 beam 1" is when base station AP1 receives a frame transmitted by terminal device STA1 using beam 1 with beam 2 when terminal device STA1 transmits a frame using beam 1. The received signal strength RSSI of "-84dBm" corresponding to "AP beam 3" and "STA1 beam 1" is the received signal strength when base station AP1 receives a frame transmitted by terminal device STA1 using beam 1 with beam 3, while the received signal strength RSSI of "-88dBm" corresponding to "AP beam 4" and "STA1 beam 1" is the received signal strength when base station AP1 receives a frame transmitted by terminal device STA1 using beam 1 with beam 4, when terminal device STA1 transmits a frame using beam 1.

[0297] Therefore, in the measurement result MR_AP1, the four received signal strength RSSI values ​​in the row direction represent the received signal strength when the receiving base station AP1 receives each frame transmitted from each of the beams 1 to 4 of the terminal devices STA1 to STAn using beams 1 to 4.

[0298] Furthermore, in the measurement result MR_AP1, the received signal strength RSSI of "-89dBm" corresponding to "AP beam 1" and "STA1 beam 1" is the received signal strength when base station AP1 receives a frame transmitted by terminal device STA1 using beam 1 when terminal device STA1 transmits a frame using beam 1, and the received signal strength RSSI of "-60dBm" corresponding to "AP beam 1" and "STA1 beam 2" is the received signal strength when base station AP1 receives a frame transmitted by terminal device STA1 using beam 2 when terminal device STA1 transmits a frame using beam 2, and base station AP1 receives a frame transmitted by terminal device STA1 using beam 1. The received signal strength RSSI of "-78dBm" corresponding to "AP beam 1" and "STA1 beam 3" is the received signal strength when base station AP1 receives a frame transmitted by terminal device STA1 using beam 3 with beam 1, while the received signal strength RSSI of "-89dBm" corresponding to "AP beam 1" and "STA1 beam 4" is the received signal strength when base station AP1 receives a frame transmitted by terminal device STA1 using beam 4 with beam 1, while terminal device STA1 transmits a frame using beam 4.

[0299] The same applies to the received signal intensity RSSI corresponding to “AP beam 1” and “STAn beam 1 to STan beam 4” in the measurement result MR_AP1.

[0300] Therefore, in the measurement result MR_AP1, the four received signal intensity RSSI values ​​in the row direction corresponding to “AP beam 1” and “STA1 beam 1 to STA1 beam 4” represent the received signal intensity when the receiving base station AP1 receives each frame transmitted from each of beams 1 to 4 of the terminal device STA1 with beam 1.

[0301] Similarly, in the measurement result MR_AP1, the four received signal strength RSSI values ​​in the row direction corresponding to “AP beam 1” and “STAn beam 1 to STan beam 4” represent the received signal strength when the receiving base station AP1 receives each frame transmitted from each of beams 1 to 4 of the terminal device STan with beam 1.

[0302] Therefore, in the measurement result MR_AP1, the four received signal strength RSSI values ​​in the column direction represent the received signal strength when the receiving base station AP1 receives each frame transmitted from each of the beams 1 to 4 of the terminal devices STA1 to STAn with beam 1.

[0303] The same applies to the measurement results MR_AP2, ..., and MR_APm.

[0304] In addition, for the measurement results MR_AP1, MR_AP2, and MR_APm shown in Figure 18, a timestamp for processing as time-series data or the transmission power of the beam transmitter for calculating propagation loss may be added.

[0305] On the other hand, measurement results measured by terminal devices STA1, STA2, ..., and STAn on the downlink are generated for each terminal device STA1, STA2, ..., and STAn. The measurement result MR_STA1 for terminal device STA1 is obtained by changing the row direction of the measurement result MR_AP1 shown in Figure 18 to "beams 1 to 4 of terminal device STA1", changing the column direction of the measurement result MR_AP1 shown in Figure 18 to "beams 1 to 4 of base station AP1" to "beams 1 to 4 of base station APm", and changing "AP1" written in the upper left of the measurement result MR_AP1 shown in Figure 18 to "STA1".

[0306] Furthermore, the measurement result MR_STA2, measured by terminal device STA2 on the downlink, is obtained by changing the row direction of the measurement result MR_AP2 shown in Figure 18 to "beams 1 to 4 of terminal device STA2", changing the column direction of the measurement result MR_AP2 shown in Figure 18 to "beams 1 to 4 of base station AP1" to "beams 1 to 4 of base station APm", and changing "AP2" written in the upper left of the measurement result MR_AP2 shown in Figure 18 to "STA2".

[0307] Similarly, the measurement result MR_STAn measured by terminal device STAn on the downlink is obtained by changing the row direction of the measurement result MR_APm shown in Figure 18 to "beam 1 to beam 4 of terminal device STAn", changing the column direction of the measurement result MR_APm shown in Figure 18 to "beam 1 to beam 4 of base station AP1" to "beam 1 to beam 4 of base station APm", and changing "APm" written in the upper left of the measurement result MR_APm shown in Figure 18 to "STAn".

[0308] For measurement results MR_STA1, MR_STA2, ..., and MR_STAn, a timestamp for processing as time-series data or the transmit power of the beam transmitter for calculating propagation loss may be added.

[0309] Figure 19 is a schematic diagram showing the aggregated measurement results in the control device 1. Referring to Figure 19, the aggregated measurement result MR_SMZ_up consists of the aggregated measurement results MR_AP1 to MR_APm shown in Figure 18. The "up" in the aggregated measurement result MR_SMZ_up indicates that the aggregated measurement result MR_SMZ_up is an aggregate of the measurement results at the uplink.

[0310] As a result, the aggregated measurement result MR_SMZ_up consists of the received signal strength RSSI when each of the base stations AP1 to APm receives each of the frames transmitted by each of the beams 1 to 4 of the terminal devices STA1 to STAn.

[0311] Furthermore, even when base stations AP1 to APm are the transmitting side and terminal devices STA1 to STAn are the receiving side, an aggregated measurement result MR_SMZ_down is created with a configuration similar to that of the aggregated measurement result MR_SMZ_up. The "down" in the aggregated measurement result MR_SMZ_down indicates that the aggregated measurement result MR_SMZ_down is an aggregate of measurement results in the downlink.

[0312] In the aggregated measurement result MR_SMZ_down, base station AP1 beam 1 to AP1 beam 4, AP2 beam 1 to AP2 beam 4, ..., APm beam 1 to APm beam 4 are stored in the row direction, and terminal devices STA1 beam 1 to STA1 beam 4, STA2 beam 1 to STA2 beam 4, ..., STAn beam 1 to STAn beam 4 are stored in the column direction.

[0313] [Connection check] The connection determination in the control device 1 will now be explained. When all measurement results are stored in the database 13, the control means 12 of the control device 1 reads all measurement results from the database 13, aggregates all measurement results, and creates the aggregated measurement result MR_SMZ_up.

[0314] The aggregated measurement results MR_SMZ_up include combinations of “AP1 beam 1 to AP1 beam 4” and “STA1 beam 1 to STA1 beam 4”, combinations of “AP1 beam 1 to AP1 beam 4” and “STA2 beam 1 to STA2 beam 4”, ..., combinations of “AP1 beam 1 to AP1 beam 4” and “STAn beam 1 to STAn beam 4”, combinations of “AP2 beam 1 to AP2 beam 4” and “STA2 beam 1 to STA2 beam 4”, and “AP2 beam 1 to AP2 beam 4” and “ST This includes combinations of A2 beam 1 to STA2 beam 4, ..., combinations of AP2 beam 1 to AP2 beam 4 and STAn beam 1 to STAn beam 4, and so on, including combinations of APm beam 1 to APm beam 4 and STA1 beam 1 to STA1 beam 4, APm beam 1 to APm beam 4 and STA2 beam 1 to STA2 beam 4, ..., and combinations of APm beam 1 to APm beam 4 and STAn beam 1 to STAn beam 4. In other words, the aggregated measurement result MR_SMZ_up includes (n × m) combinations.

[0315] Then, based on the aggregated measurement result MR_SMZ_up, the control means 12 detects the beam number for each AP-STA combination that yields the largest received signal strength RSSI.

[0316] Subsequently, the control means 12 determines whether the highest received signal intensity RSSI_max is equal to or greater than a threshold (for example, -60 dBm). When the control means 12 determines that the highest received signal intensity RSSI_max is equal to or greater than the threshold, it determines that the beam at which the highest received signal intensity RSSI_max is obtained can be connected. When the control means 12 determines that the highest received signal intensity RSSI_max is not equal to or greater than the threshold, it determines that the beam at which the highest received signal intensity RSSI_max is obtained cannot be connected.

[0317] When the control means 12 determines that the beam with the highest received signal intensity RSSI_max is connectable, it determines the ID of the base station AP (=AP_ID) and the beam number b of the connectable base station AP. APThe ID of the terminal device STA (=STA_ID) and the beam number b of the connectable terminal device STA. STA The pair {AP_ID,b AP STA_ID,b STA Create}.

[0318] Then, the control means 12 sets {AP_ID,b AP STA_ID,b STA Based on this, connection information IF_CNT_AP for base station AP and connection information IF_CNT_STA for terminal device STA are created.

[0319] The control means 12 controls each of the (n × m) combinations shown in Figure 19 using the method described above, for each of the set {AP_ID,b AP STA_ID,b STA Create} and the set {AP_ID,b AP STA_ID,b STA Based on this, connection information IF_CNT_AP for base station APs and connection information IF_CNT_STA for terminal devices STAs are created.

[0320] The control means 12 then outputs (n × m) connection destination information IF_CNT_AP and (n × m) connection destination information IF_CNT_STA to the communication means 11.

[0321] When the communication means 11 receives (n × m) connection destination information IF_CNT_AP and (n × m) connection destination information IF_CNT_STA from the control means 12, it transmits (n × m) connection destination information IF_CNT_AP to all base station APs using the backhaul line BHC, and transmits (n × m) connection destination information IF_CNT_STA to the base station AP to which the terminal device STA is connected using the backhaul line BHC.

[0322] As a result, all base station APs receive (n × m) pieces of destination information IF_CNT_AP via the backhaul circuit BHC. When a base station AP to which a terminal device STA is connected receives (n × m) pieces of destination information IF_CNT_STA via the backhaul circuit BHC, it transmits the destination information, including the terminal device STA it is connected to, from among the received (n × m) pieces of destination information IF_CNT_STA to the terminal device STA it is connected to. The terminal device STA then receives the destination information IF_CNT_STA from the base station AP to which it is connected.

[0323] Figure 20 is a schematic diagram of connection destination information for base station APs and terminal devices STAs.

[0324] Figure 20(a) shows the connection information for base station AP1, Figure 20(b) shows the connection information for terminal device STA1, Figure 20(c) shows the connection information for base station AP2, and Figure 20(d) shows the connection information for terminal device STA2.

[0325] In Figures 20(a) to (d), "NA" indicates that none of the beams are available.

[0326] Referring to Figure 20(a), the connection information for base station AP1 indicates that beam 2 of base station AP1 is connectable to the destination terminal device STA1.

[0327] Furthermore, the connection information for base station AP1 indicates that base station AP1 does not have a beam capable of connecting to the destination terminal device STA2.

[0328] Referring to Figure 20(b), the connection information for terminal device STA1 indicates that beam 4 of terminal device STA1 is connectable to base station AP1, which is the connection destination.

[0329] Furthermore, the connection information for terminal device STA1 indicates that terminal device STA1 does not have a beam capable of connecting to base station AP2, which is the connection destination.

[0330] Furthermore, referring to Figure 20(c), the connection information for base station AP2 indicates that beam 3 of base station AP2 is connectable to the destination terminal device STA2.

[0331] Furthermore, the connection information for base station AP2 indicates that base station AP2 does not have a beam capable of connecting to the destination terminal device STA1.

[0332] Furthermore, referring to Figure 20(d), the connection destination information for terminal device STA2 indicates that terminal device STA2 does not have a beam capable of connecting to base station AP1, which is the connection destination.

[0333] Furthermore, the connection destination information for terminal device STA2 indicates that beam 4 of terminal device STA2 is capable of connecting to base station 2, which is the connection destination.

[0334] Furthermore, in the aggregated measurement results MR_SMZ_up shown in Figure 19, the maximum received signal strength RSSI = -60 dBm was obtained with the combination of “AP1 beam 1” - “STA1 beam 1” ~ “STA1 beam 4”, the maximum received signal strength RSSI = -58 dBm was obtained with the combination of “AP1 beam 2” - “STA1 beam 1” ~ “STA1 beam 4”, the maximum received signal strength RSSI = -62 dBm was obtained with the combination of “AP1 beam 3” - “STA1 beam 1” ~ “STA1 beam 4”, and the maximum received signal strength RSSI = -75 dBm was obtained with the combination of “AP1 beam 4” - “STA1 beam 1” ~ “STA1 beam 4”.

[0335] Of these maximum received signal strength RSSIs, the highest received signal strength RSSIs that are above the threshold (=-60dBm) are -60dBm and -58dBm.

[0336] As a result, the configuration that yields -60 dBm (AP1 beam 1, STA1 beam 2) is determined to be connectable, and the configuration that yields -58 dBm (AP1 beam 2, STA1 beam 1) is also determined to be connectable.

[0337] Then, set {1,1,1,2} is obtained for a received signal strength RSSI of -60 dBm, and set {1,2,1,1} is obtained for a received signal strength RSSI of -58 dBm.

[0338] Then, the control means 12 of the control device 1 generates connection destination information for the base station AP and connection destination information for the terminal device STA based on the sets {1,1,1,2} and {1,2,1,1}.

[0339] Figure 21 is a schematic diagram of connection destination information for base station APs and terminal devices STAs, created based on the sets {1,1,1,2} and {1,2,1,1}.

[0340] Referring to Figure 21, Figure 21(a) shows the connection destination information for base station PA1, and Figure 21(b) shows the connection destination information for terminal device STA1.

[0341] In the pair {1,1,1,2}, the underlined "1" represents the ID of terminal device STA1, and the underlined "1" in the pair {1,1,1,2} represents the beam number of base station AP1. Therefore, the beam with beam number = 1 of base station AP1 is connectable to the destination terminal device STA1 (see Figure 21(a)).

[0342] Furthermore, the underlined "1" in the set {1,2,1,1} represents the ID of terminal device STA1, and the underlined "2" in the set {1,2,1,1} represents the beam number of base station AP1. Therefore, the beam with beam number 2 of base station AP1 is connectable to the destination terminal device STA1 (see Figure 21(a)).

[0343] Therefore, the connection information for AP1 shown in Figure 21(a) is created.

[0344] Furthermore, the underlined "2" in the set {1,1,1,2} represents the beam number of terminal device STA1, and the underlined "1" in the set {1,1,1,2} represents the identification information of base station AP1. Therefore, the beam with beam number = 2 of terminal device STA1 is connectable to the destination base station AP1 (see Figure 21(b)).

[0345] Furthermore, the underlined "1" in the set {1,2,1,1} represents the beam number of terminal device STA1, and the underlined "1" in the set {1,2,1,1} represents the identification information of base station AP1. Therefore, the beam with beam number = 1 of terminal device STA1 indicates that it can connect to the destination base station AP1 (see Figure 21(b)).

[0346] As a result, connection destination information for AP1 and connection destination information for STA1, as shown in Figure 21, are created.

[0347] Figure 22 is a flowchart illustrating the operation of the communication system 10 according to an embodiment of this invention.

[0348] Referring to Figure 22, once the operation of the communication system 10 begins, the control device 1 of the communication system 10 determines whether or not a connection determination is necessary (step S21).

[0349] In this case, the control device 1 determines that a connection check is necessary when it determines that a new terminal device has entered the communication system 10, and determines that a connection check is not necessary when it determines that a new terminal device has not entered the communication system 10.

[0350] In step S21, when the control device 1 determines that a connection determination is necessary, the control device 1 determines whether m is greater than or equal to n (i.e., whether the number of base stations m is greater than or equal to the number of terminal devices n) (step S22).

[0351] In step S22, when it is determined that m is greater than or equal to n (i.e., the number of base stations m is greater than or equal to the number of terminal devices n), the following are performed sequentially in step S23: (I) a scan schedule is sent to all terminal devices and base stations; (II) the received signal strength is measured when a terminal device transmits and a base station receives the signal; and (III) the measurement results are sent from each base station to the control device.

[0352] On the other hand, in step S22, if it is determined that m is not greater than or equal to n (i.e., the number of base stations m is less than the number of terminal devices n), the following actions are performed sequentially: (I) transmit the scan schedule to all terminal devices and base stations; (IV) measure the received signal strength when transmitted by a base station and received by a terminal device; (V) transmit the measurement results from the terminal device to the connected base station; and (VI) transmit the measurement results from the base station to which the terminal device is connected to the control device (step S24).

[0353] Then, after step S23 or step S24, the control device 1 performs a connection determination (step S25).

[0354] In that case, if it is determined in step S21 that a connection check is not necessary, or after step S25, the operation of the communication system 10 ends.

[0355] Figure 23 is a flowchart illustrating the detailed operation of step S23 in Figure 22.

[0356] Referring to Figure 23, in step S22, when it is determined that m is greater than or equal to n (i.e., the number of base stations m is greater than or equal to the number of terminal devices n), the control device 1 transmits a scan schedule to each base station using the backhaul line BHC (step S23-1).

[0357] Then, all base stations receive the scan schedule via the backhaul circuit (BHC). Subsequently, any base station that is connected to a terminal device transmits the scan schedule to the connected terminal device (step S23-2).

[0358] Then, all base stations and terminal devices set i=1 (step S23-3), j=1 (step S23-4), and k=1 (step S23-5).

[0359] Here, "i" is the argument of the terminal device, "j" is the beam argument of the terminal device, and "k" is the beam argument of the base station.

[0360] After step S23-5, all terminal devices except the i-th terminal device STAi enter sleep mode (step S23-6). In this case, all terminal devices except the i-th terminal device STAi enter sleep mode by referring to the scanning schedule.

[0361] After step S23-6, the i-th terminal device STAi, which is the subject of the connection determination, transmits a frame using beam j (step S23-7).

[0362] Then, all base stations synchronize to receive the frame transmitted using beam j with beam k (step S23-8). Each base station then detects the received signal strength RSSI when it receives the frame with beam k, and also detects the beam number of beam j from the frame transmitted with beam j, and creates a measurement result [beam number / received signal strength RSSI].

[0363] Then, all base stations determine whether k=x or not (step S23-9).

[0364] In step S23-9, if it is determined that k=x, all base stations set k=k+1 (step S23-10).

[0365] Subsequently, the operation of the communication system 10 proceeds to step S23-6, and steps S23-6 to S23-10 are repeatedly executed until it is determined in step S23-9 that k=x.

[0366] Then, in step S23-9, if it is determined that k=x, all base stations determine whether j=y or not (step S23-11).

[0367] In step S23-11, if it is determined that j=y, all base stations set j=j+1 (step S23-12).

[0368] Subsequently, the operation of the communication system 10 proceeds to step S23-5, and steps S23-5 to S23-12 are repeatedly executed until it is determined in step S23-11 that j=y.

[0369] Then, in step S23-11, if it is determined that j=y, all base stations determine whether i=n or not (step S23-13).

[0370] In step S23-13, if it is determined that i=n, ​​all base stations set i=i+1 (step S23-14).

[0371] Subsequently, the operation of the communication system 10 proceeds to step S23-4, and steps S23-4 to S23-14 are repeatedly executed until it is determined in step S23-13 that i=n.

[0372] Then, in step S23-13, if it is determined that i=n, ​​each base station transmits the measurement result to the control device 1 using the backhaul line BHC (step S23-15).

[0373] Subsequently, the control unit receives measurement results from each base station (step S23-16).

[0374] Then, after step S23-16, the operation of the communication system 10 proceeds to step S25 in Figure 22.

[0375] In the flowchart shown in Figure 23, the repeated execution of steps S23-6 to S23-10 until it is determined in step S23-9 that k=x corresponds to all base stations (=m base stations) synchronously scanning their beams sequentially from beam 1 to beam x and receiving the frame transmitted using beam j of terminal device STAi when all terminal devices other than the i-th terminal device STAi are in a sleep state.

[0376] Furthermore, in the flowchart shown in Figure 23, the repeated execution of steps S23-5 to S23-12 until it is determined in step S23-11 that j=y corresponds to all base stations (=m base stations) synchronously scanning the beams sequentially from beam 1 to beam x and receiving the frame transmitted by the i-th terminal device STAi using beam j for all y beams 1 to beam y scanned by the i-th terminal device STAi.

[0377] Furthermore, in the flowchart shown in Figure 23, the repeated execution of steps S23-4 to S23-14 until it is determined in step S23-13 that i=n corresponds to all base stations (=m base stations) synchronously performing a beam scanning process for all terminal devices (=n terminal devices) that sequentially scans the beams from beam 1 to beam x to receive the frame transmitted by the i-th terminal device STAi using beam j, while all terminal devices other than the i-th terminal device STAi are in a sleep state.

[0378] In this way, if all base stations (=m base stations) synchronously perform beam scanning processing for all terminal devices (=m terminal devices), and if all base stations (=m base stations) simultaneously receive frames transmitted using beam j of the terminal devices y times, then all base stations (=m base stations) will have received all frames transmitted using y beams 1 to y transmitted from the terminal devices.

[0379] On the other hand, if each base station receives frames transmitted using y beams 1 to y from the terminal device at different timings, the number of times m base stations receive frames transmitted from the terminal device is (m × y).

[0380] Therefore, compared to the case where each base station receives y beams 1 to y from a terminal device at different timings, the number of receptions required to receive frames transmitted using y beams 1 to y from a terminal device can be reduced. As a result, the connection determination process or resources can be reduced.

[0381] Figure 24 is a flowchart illustrating the detailed operation of step S24 in Figure 22.

[0382] The flowchart shown in Figure 24 is the same as the flowchart in Figure 23, except that steps S23-3 to S23-15 are changed to steps S24-1 to S24-13.

[0383] Referring to Figure 24, if it is determined in step S22 above that m is not greater than or equal to n (i.e., if it is determined that the number of base stations m is less than the number of terminal devices n), then steps S23-1 and S23-2 are executed sequentially.

[0384] Then, after step S23-2, all base stations and terminal devices set p=1 (step S24-1), k=1 (step S24-2), and j=1 (step S24-3). Here, "p" is the argument of the base station.

[0385] After step S24-3, all base stations except the p-th base station enter sleep mode (step S24-4). In this case, the base stations other than the p-th base station enter sleep mode by referring to the scan schedule.

[0386] After step S24-4, the p-th base station, which is the subject of the connection determination, transmits a frame using beam k (step S24-5).

[0387] Then, all terminal devices synchronize to receive the frame transmitted using beam k with beam j (step S24-6). Each terminal device then detects the received signal strength RSSI when it receives beam k and also detects the beam number of beam k from the frame transmitted using beam k, and creates a measurement result [beam number / received signal strength RSSI].

[0388] Then, all terminal devices determine whether j=y or not (step S24-7).

[0389] In step S24-7, if it is determined that j=y is not true, all terminal devices set j=j+1 (step S24-8).

[0390] Subsequently, the operation of the communication system 10 proceeds to step S24-4, and steps S24-4 to S24-8 are repeatedly executed until it is determined in step S24-7 that j=y.

[0391] Then, in step S24-7, if it is determined that j=y, all terminal devices determine whether or not k=x (step S24-9).

[0392] In step S24-9, if it is determined that k=x, all terminal devices set k=k+1 (step S24-10).

[0393] Subsequently, the operation of the communication system 10 proceeds to step S24-3, and steps S24-3 to S24-10 are repeatedly executed until it is determined in step S24-9 that k=x.

[0394] Then, in step S24-9, if it is determined that k=x, all terminal devices determine whether or not p=m (step S24-11).

[0395] In step S24-11, if it is determined that p=m is not true, all terminal devices set p=p+1 (step S24-12).

[0396] Subsequently, the operation of the communication system 10 proceeds to step S24-2, and steps S24-2 to S24-12 are repeatedly executed until it is determined in step S24-11 that p=m.

[0397] Then, in step S24-11, if it is determined that p=m, each terminal device transmits the measurement result to the base station it is connected to (step S24-13).

[0398] Subsequently, step S23-16 described above is performed, and after step S23-16, the operation of the communication system 10 proceeds to step S25 in Figure 22.

[0399] In the flowchart shown in Figure 24, the repeated execution of steps S24-4 to S24-8 until it is determined in step S24-7 that j=y corresponds to all terminal devices (=n terminal devices) synchronously scanning the beam sequentially from beam 1 to beam y to receive the frame transmitted using beam k of the p-th base station when all base stations except the p-th base station are in a sleep state.

[0400] Furthermore, in the flowchart shown in Figure 24, the repeated execution of steps S24-3 to S24-10 until it is determined in step S24-9 that k=x corresponds to all terminal devices (=n terminal devices) synchronously scanning the beam sequentially from beam 1 to beam y to receive frames transmitted using beam k of the p-th base station, when all base stations except the p-th base station are in a sleep state.

[0401] Furthermore, in the flowchart shown in Figure 24, the repeated execution of steps S24-2 to S24-12 until it is determined in step S24-11 that p=m corresponds to all terminal devices (=n terminal devices) synchronously performing a beam scanning process for all x beams 1 to x scanned by the p-th base station, where the receiving process involves sequentially scanning the beams from beam 1 to beam y to receive frames transmitted using beam k of the p-th base station.

[0402] In this way, if all terminal devices (=n terminal devices) synchronously perform beam scanning processing for all base stations (=m base stations), and if all terminal devices (=n terminal devices) simultaneously receive frames transmitted using the base station's beam k, and this is done x times, then all terminal devices (=n terminal devices) will have received all x beams 1 to x transmitted from the base station.

[0403] On the other hand, if each terminal device receives frames transmitted using x beams 1 to x transmitted from the base station at different timings, the number of times n terminal devices receive frames transmitted from the base station is (n × x).

[0404] Therefore, compared to the case where each terminal device receives frames transmitted using x beams 1 to x of the base station at different timings, the number of times it receives frames transmitted using x beams 1 to x of the base station can be reduced. As a result, the connection determination process or resources can be reduced.

[0405] Figure 25 is a flowchart illustrating the detailed operation of step S25 in Figure 22.

[0406] Referring to Figure 25, after step S23 or step S24 in Figure 22, the control means 12 of the control device 1 reads all measurement results from the database 13 and aggregates all the read measurement results (step S251).

[0407] Then, the control means 12 sets z=1 (step S252). Here, z is an argument that indicates the combination of each base station and each terminal device.

[0408] After step S252, the control means 12, based on the aggregated measurement results, determines the beam number b for each combination z of base stations and terminal devices when the maximum received signal strength RSSI_max_z is obtained. STA_z ,b AP_z Detect (step S253).

[0409] Then, the control means 12 determines whether the maximum received signal strength RSSI_max_z is greater than or equal to a threshold (step S254).

[0410] In step S254, when it is determined that the maximum received signal strength RSSI_max_z is equal to or greater than the threshold, the control means 12 determines that the beam at which the maximum received signal strength RSSI_max_z is obtained can be connected (step S255).

[0411] The control means 12 then receives the base station identification information AP_ID and the beam number b of the connectable base station. AP_zTerminal device identification information STA_ID, beam number of connectable terminal device b STA_z The pair {AP_ID,b AP_z STA_ID,b STA_z Create} (step S256).

[0412] Subsequently, the control means 12 sets {AP_ID,b AP_z STA_ID,b STA_z Based on}, the connection destination information for the base station is IF_CNT_AP z And, connection information for terminal devices IF_CNT_STA z Create (step S257).

[0413] Subsequently, the control means 12 transmits connection destination information IF_CNT_AP to the base station via the communication means 11 and the backhaul line BHC. z The following information is transmitted to all base station APs, and connection destination information IF_CNT_STA for terminal devices is sent via communication means 11 and backhaul line BHC. z The terminal device transmits this to the base station to which it is connected (step S258).

[0414] On the other hand, in step S254, if the control means 12 determines that the maximum received signal strength RSSI_max_z is not equal to or greater than the threshold, it determines that the beam at which the maximum received signal strength RSSI_max_z is obtained cannot be connected (step S259).

[0415] Then, after step S258 or step S259, the control means 12 determines whether z = Z (step S260). Here, Z is the total number of combinations of each base station and each terminal device.

[0416] In step S260, if it is determined that z=Z, the control means 12 sets z=z+1 (step S261). Subsequently, the detailed operation of step S25 proceeds to step S253, and steps S253 to S261 are repeatedly executed until it is determined in step S260 that z=Z.

[0417] Then, in step S260, if it is determined that z=Z, the operation of the communication system 10 proceeds to “termination” as shown in Figure 22.

[0418] Figure 26 is a flowchart illustrating the operation of the control device 1. Referring to Figure 26, when the operation of the control device 1 begins, the control means 12 sets g=1 (step S31), and the communication means 11 receives connection information IF_CNT_g, which indicates the connection relationship between the base station and the terminal device, from the base station AP_g via the backhaul line BHC (step S32). Note that g is an argument indicating the connection information.

[0419] The communication means 11 then outputs connection information IF_CNT_g to the control means 12. When the control means 12 receives the connection information IF_CNT_g from the communication means 11, it refers to its built-in timer and determines the time t when the connection information IF_CNT_g was received. g It detects the connection information IF_CNT_g and sets the time t g The data is associated with the database 13 and stored (step S33).

[0420] Then, the control means 12 determines whether g = G or not (step S34). Here, G is the total number of connection information.

[0421] In step S34, if it is determined that g=G, the control means 12 sets g=g+1 (step S35). Subsequently, the operation of the control device 1 proceeds to step S32, and steps S32 to 35 are repeatedly executed until it is determined in step S34 that g=G.

[0422] Then, in step S34, when it is determined that g=G, the control means 12 determines whether or not a connection determination is necessary using the method described above (step S36).

[0423] In step S36, if it is determined that a connection check is necessary, the control means 12 detects the number of base stations n and the number of terminal devices m based on Q pieces of connection information IF_CNT_1 to IF_CNT_G (step S37).

[0424] Then, the control means 12 determines whether m is greater than or equal to n (step S38).

[0425] In step S38, if it is determined that m is not greater than or equal to n (i.e., if it is determined that m is less than n), the control means 12 creates a first scan schedule (step S39). The control means 12 then outputs the first scan schedule to the communication means 11.

[0426] Here, the first scanning schedule is a scanning schedule for all m base stations to perform a first beam scanning process, which is performed for all beams scanned by one base station, in which n terminal devices synchronously receive a frame transmitted using one beam from one of the m base stations while scanning the beam. As shown in Figure 17, during scanning period TS1, base station AP1 transmits a frame using beam 1, and terminal devices STA1, STA2, and STAn synchronously receive the frame transmitted by base station AP1 using beam 1 sequentially with beams 1 to 4. During scanning period TS2, base station AP1 transmits a frame using beam 2, and terminal devices STA1, STA2, and STAn synchronously receive the frame transmitted by base station AP1 using beam 2 sequentially with beams 1 to 4. During scanning period TS3, base station AP1 transmits a frame using beam 3, and terminal devices STA1, STA2, and STAn synchronously receive the frame transmitted by base station AP1 using beam 3 sequentially with beams 1 to 4. During scanning period TS4, base station AP1 transmits a frame using beam 4, and terminal devices STA1, STA2, and STAn synchronously receive the frame transmitted by base station AP1 using beam 4 sequentially with beams 1 to 4.

[0427] On the other hand, if it is determined in step S38 that m is greater than or equal to n, the control means 12 creates a second scanning schedule (step S40). The control means 12 then outputs the second scanning schedule to the communication means 11.

[0428] Here, the second scanning schedule is a scanning schedule for all n terminal devices to perform a second beam scanning process, which is performed for all beams scanned by one terminal device, in which m base stations synchronously scan the beam to receive a frame transmitted using one beam from one of the n terminal devices. As shown in Figure 16, during scanning period TS1, terminal device STA1 transmits a frame using beam 1, and base stations AP1, AP2, and APm synchronously receive the frame transmitted by terminal device STA1 using beam 1 sequentially with beams 1 to 4. During scanning period TS2, terminal device STA1 transmits a frame using beam 2, and base stations AP1, AP2, and APm synchronously receive the frame transmitted by terminal device STA1 using beam 2 sequentially with beams 1 to 4. During scanning period TS3, terminal device STA1 transmits a frame using beam 3, and base stations AP1, AP2, and APm synchronously receive the frame transmitted by terminal device STA1 using beam 3 sequentially with beams 1 to 4. During scanning period TS4, terminal device STA1 transmits a frame using beam 4, and base stations AP1, AP2, and APm synchronously receive the frame transmitted by terminal device STA1 using beam 4 sequentially with beams 1 to 4.

[0429] Then, after step S39 or step S40, the communication means 11 transmits the first or second scan schedule to all base stations via the backhaul line BHC (step S41).

[0430] Subsequently, the communication means 11 receives measurement results from all base stations via the backhaul line BHC (step S42). Then, the communication means 11 outputs the measurement results to the control means 12.

[0431] The control means 12 refers to the built-in timer and determines the time t when it receives the measurement result from the communication means 11. s It detects and measures the time t s The data is associated with the database 13 and stored in it (step S43).

[0432] Subsequently, the control means 12 sequentially executes steps S251 to S261 in Figure 25 (step S44).

[0433] Then, in step S36, if it is determined that a connection check is not necessary, or after step S44, the operation of the control device 1 ends.

[0434] According to the flowchart shown in Figure 26, the control means 12 creates a first scan schedule or a second scan schedule according to the relationship between the number of base stations m and the number of terminal devices n (see steps S37 to S40).

[0435] The first scanning schedule is a scanning schedule for all m base stations to perform a first beam scanning process, which is performed for all beams scanned by one base station, in which n terminal devices synchronously receive a frame transmitted using one beam from one of the m base stations using one beam.

[0436] Furthermore, the second scanning schedule is a scanning schedule for all n terminal devices to perform a second beam scanning process, which is performed for all beams scanned by one terminal device, in which m base stations synchronously scan the beam to receive a frame transmitted using one beam from one of the n terminal devices.

[0437] Therefore, when the number of base stations m is not greater than or equal to the number of terminal devices n (i.e., when the number of base stations m is less than the number of terminal devices n), the control means 12 creates a first scanning schedule for all m base stations, in which a first receiving process is performed for all beams scanned by one base station, in which n terminal devices synchronously scan the beam to receive a frame transmitted from one of the m base stations using one beam (see step S39). Thus, when the m base stations and n terminal devices scan the beams based on the first scanning schedule, the first beam scanning process is performed for all m base stations, in which a first receiving process is performed for all beams scanned by one base station, in which n terminal devices synchronously scan the beam to receive a frame transmitted from one base station using one beam.

[0438] As a result, the number of times (=y) that n terminal devices scan the beam based on the first scanning schedule is less than the number of times (=n×y) that would occur if each of the n terminal devices scanned the beam at different timings. Therefore, the number of times that n terminal devices scan the beam can be reduced, and the resources required when n terminal devices scan the beam can be reduced.

[0439] Furthermore, when the number of base stations m is equal to or greater than the number of terminal devices n, the control means 12 creates a second scanning schedule for all n terminal devices, in which a second receiving process is performed for all beams scanned by one terminal device, in which the m base stations synchronously scan the beams to receive a frame transmitted from one of the n terminal devices using one beam (see step S40). Therefore, when the m base stations and n terminal devices scan the beams based on the second scanning schedule, the second beam scanning process is performed for all n terminal devices, in which the m base stations synchronously scan the beams to receive a frame transmitted from one terminal device using one beam, in which the second receiving process is performed for all beams scanned by one base station.

[0440] As a result, the number of times (=x) that m base stations scan the beam based on the second scanning schedule is less than the number of times (=m × x) that would occur if each of the m base stations scanned the beam at different times. Therefore, the number of times that m base stations scan the beam can be reduced, and the resources required when m base stations scan the beam can be reduced.

[0441] Figure 27 is a flowchart illustrating the operation of base station 2. Referring to Figure 27, when base station 2 starts operating, the control means 26 of base station 2 determines whether or not there are terminal devices connected to it (step S51). Since the control means 26 of base station 2 recognizes terminal devices that are communicating with base station 2, in step S51, if there are terminal devices communicating with base station 2, it determines that there are terminal devices connected to it, and if there are no terminal devices communicating with base station 2, it determines that there are no terminal devices connected to it.

[0442] In step S51, if it is determined that there is a terminal device connected to itself, the control means 26 creates connection information indicating the connection relationship between the base station 2 and the terminal device connected to the base station 2 (step S52).

[0443] The control means 26 then outputs connection information to the communication means 27. Upon receiving the connection information from the control means 26, the communication means 27 transmits the connection information to the control device via the backhaul line BHC (step S53).

[0444] Subsequently, the communication means 27 receives the scan schedule from the control device 1 via the backhaul line BHC (step S54) and outputs the received scan schedule to the control means 26. In this case, the communication means 27 receives either the first scan schedule or the second scan schedule described above.

[0445] When the control means 26 receives a scan schedule (= first scan schedule or second scan schedule) from the communication means 27, it holds the scan schedule (= first scan schedule or second scan schedule) and outputs the scan schedule (= first scan schedule or second scan schedule) to the wireless communication means 24, controlling the wireless communication means 24 to transmit the scan schedule (= first scan schedule or second scan schedule) to a terminal device connected to the base station 2.

[0446] When the wireless communication means 24 receives a scanning schedule (= first scanning schedule or second scanning schedule) from the control means 26, it controls the beamforming means 21 to radiate a microwave band beam from the antenna 21A and outputs the scanning schedule (= first scanning schedule or second scanning schedule) to the antenna 21A. As a result, the scanning schedule (= first scanning schedule or second scanning schedule) is transmitted to the terminal device connected to the base station 2 (step S55).

[0447] After step S55, the control means 26 refers to the scanning schedule (= first scanning schedule or second scanning schedule) to determine whether the base station 2 is the destination for the beamframe transmission (step S56).

[0448] In this case, the control means 26 determines that when the scanning schedule is the first scanning schedule, the base station 2 is not a destination for beam-based frame transmission, and when the scanning schedule is the second scanning schedule, the base station 2 is a destination for beam-based frame transmission.

[0449] In step S56, when it is determined that base station 2 is the destination of a beam-based frame, base station 2 scans the beam through k beams and receives the frame transmitted using beam i of the terminal device for y beams from the terminal device, detecting y received signal intensities and y beam numbers to create a measurement result (step S57).

[0450] On the other hand, in step S56, if it is determined that base station 2 is not the destination for a frame using a beam, base station 2 scans the beam into x beams and transmits frames sequentially using x beams (step S58).

[0451] Subsequently, the wireless communication means 24 of the base station 2 receives the measurement result from the terminal device connected to itself (base station 2) via the antenna 21A (step S59), and outputs the received measurement result to the control means 26.

[0452] After step S57 or step S59, the control means 26 outputs the measurement result to the communication means 27. Upon receiving the measurement result from the control means 26, the communication means 27 transmits the measurement result to the control device 1 via the backhaul line BHC (step S60).

[0453] Then, the communication means 27 of base station 2 receives from the control device 1, via the backhaul circuit BHC, connection destination information addressed to itself (to base station 2) and connection destination information addressed to terminal devices connected to itself (base station 2) (step S61).

[0454] Subsequently, the control means 26 outputs connection destination information for terminal devices connected to itself (base station 2) to the wireless communication means 24.

[0455] When the wireless communication means 24 receives connection destination information for a terminal device connected to itself (base station 2) from the control means 26, it controls the beamforming means 21 to emit a microwave band beam from the antenna 21A and outputs the connection destination information for the terminal device to the antenna 21A. As a result, the connection destination information for the terminal device is transmitted to the terminal device connected to base station 2 (step S62). With this, the operation of base station 2 ends.

[0456] Figure 28 is a flowchart illustrating the detailed operation of step S57 in Figure 27.

[0457] Referring to Figure 28, in step S56 of Figure 27, when it is determined that base station 2 is the destination for transmitting a beamframe, the control means 26 of base station 2 sets k=1 (step S571).

[0458] The control means 26 then controls the wireless communication means 24 to sequentially form x beams 1 to x in the terahertz band.

[0459] Then, the wireless communication means 24 controls the beamforming means 23 so that the antenna 23A forms beam k of beam number k.

[0460] The beamforming means 23 then forms beam k of beam number k at antenna 23A by analog beamforming or digital beamforming.

[0461] As a result, the wireless communication means 24 receives the frame transmitted using beam j of the terminal device via antenna 23A with beam k (step S572), and acquires the received signal.

[0462] The wireless communication means 24 then outputs the received signal to the measuring means 25. When the measuring means 25 receives the received signal from the wireless communication means 24, it measures the received signal intensity RSSI at the time the received signal was received and detects the beam number from the frame transmitted using beam k.

[0463] Then, the measuring means 25 outputs the received signal strength RSSI and beam number to the control means 26. The control means 26 receives the received signal strength RSSI and beam number from the measuring means 25 and creates a measurement result including the received received signal strength RSSI and beam number (step S573).

[0464] Subsequently, the control means 26 determines whether or not k=x (step S574).

[0465] In step S574, if it is determined that k=x, the control means 26 sets k=k+1 (step S575). Subsequently, the operation of the base station 2 proceeds to step S572, and steps S572 to S575 are repeatedly executed until it is determined in step S574 that k=x.

[0466] Then, if it is determined in step S574 that k=x, the operation of base station 2 proceeds to step S60 in Figure 27.

[0467] Figure 29 is a flowchart illustrating the detailed operation of step S58 in Figure 27.

[0468] Referring to Figure 29, in step S56 of Figure 27, if it is determined that the base station 2 is not the destination for the beamframe transmission, the control means 26 of the base station 2 sets k=1 (step S581).

[0469] The control means 26 then controls the wireless communication means 24 to form a terahertz beam k.

[0470] Then, the wireless communication means 24 controls the beamforming means 23 so that the antenna 23A forms beam k of beam number k.

[0471] Then, the beamforming means 23 forms beam k of beam number k at antenna 23A by analog beamforming or digital beamforming and transmits the frame (step S582).

[0472] Subsequently, the control means 26 determines whether or not k=x (step S583).

[0473] In step 583, if it is determined that k is not equal to x, the control means sets k to k+1 (step S584). Subsequently, the operation of base station 2 proceeds to step S582, and steps S582 to S584 are repeatedly executed until it is determined in step S583 that k is equal to x.

[0474] Then, if it is determined in step S583 that k=x, the operation of base station 2 proceeds to step S59 in Figure 27.

[0475] Furthermore, the operations of each of the base stations 3 to 6 are performed according to the flowchart shown in Figure 27 (including the flowcharts shown in Figures 28 and 29).

[0476] Figure 30 is a flowchart illustrating the operation of the terminal device 7. Referring to Figure 30, when the operation of the terminal device 7 begins, the wireless communication means 74 receives a scan schedule from the base station to which the terminal device 7 is connected via the antenna 21A, which is controlled by the beamforming means 71 to form a microwave beam (step S71), and outputs the received scan schedule to the control means 76.

[0477] The control means 76 receives the scanning schedule from the wireless communication means 74. The control means 76 then refers to the scanning schedule and determines whether the terminal device 7 is the destination for transmitting beamframes (step S72).

[0478] In step S72, when it is determined that terminal device 7 is the destination for transmitting a beamframe, the control means 76 sets k=1 (step S73).

[0479] The control means 76 then controls the wireless communication means 74 to form y beams 1 to y beams y with the antenna 73A. The wireless communication means 74 controls the beamforming means 73 to form y beams 1 to y beams y in the terahertz band with the antenna 73A in response to the control means 76.

[0480] The beamforming means 73 then forms y beams 1 to y on the antenna 73A by analog beamforming or digital beamforming.

[0481] As a result, the wireless communication means 74 receives the frame transmitted using the base station's beam k via the antenna 73A by scanning it with y beams 1 to y (step S74), and acquires y received signals.

[0482] The wireless communication means 74 then outputs y received signals to the measuring means 75. When the measuring means 75 receives y received signals from the wireless communication means 74, it measures the y received signal intensities RSSI_1 to RSSI_y at the time the y received signals were received, and also detects y beam numbers b_1 to b_y from the y frames transmitted using y beams 1 to y.

[0483] Then, the measuring means 75 outputs the received signal intensities RSSI_1 to RSSI_y and beam numbers b_1 to b_y to the control means 76. The control means 76 receives the received signal intensities RSSI_1 to RSSI_y and beam numbers b_1 to b_y from the measuring means 75 and creates measurement results MR_1 to MR_y that include the received received signal intensities RSSI_1 to RSSI_y and beam numbers b_1 to b_y (step S75).

[0484] Then, the control means 76 determines whether or not k=x (step S76).

[0485] In step S76, if it is determined that k is not equal to x, the control means 76 sets k to k+1 (step S77). Subsequently, the operation of the terminal device 7 proceeds to step S74, and steps S74 to S77 are repeatedly executed until it is determined in step S76 that k is equal to x.

[0486] Then, in step S76, if it is determined that k=x, the control means 76 outputs the measurement result {MR_1~MR_y}_1~{MR_1~MR_y}_x to the wireless communication means 74.

[0487] When the wireless communication means 74 receives the measurement results {MR_1~MR_y}_1~{MR_1~MR_y}_x from the control means 76, it controls the beamforming means 71 to transmit a microwave beam from the antenna 71A.

[0488] The beamforming means 71 then emits a microwave beam from the antenna 71A by analog beamforming or digital beamforming.

[0489] As a result, the wireless communication means 74 transmits the measurement results {MR_1~MR_y}_1~{MR_1~MR_y}_x via the antenna 71A to the base station to which the terminal device is connected (step S78).

[0490] On the other hand, in step S72, if it is determined that the terminal device 7 is not the destination for transmitting a beamframe, the wireless communication means 74 sets j=1 (step S79) and controls the beamforming means 73A to form beam j.

[0491] Then, the beamforming means 73A forms a beam j from the antenna 73A by analog beamforming or digital beamforming and transmits the frame (step S80).

[0492] Subsequently, the wireless communication means 74 determines whether j=y or not (step S81).

[0493] In step S81, if it is determined that j=y, the wireless communication means 74 sets j=j+1 (step S82). Subsequently, the operation of the terminal device 7 proceeds to step S80, and steps S80 to S82 are repeatedly executed until it is determined in step S81 that j=y.

[0494] Then, if it is determined in step S81 that j=y, the operation of the terminal device 7 proceeds to step S83.

[0495] Then, after step S78, or in step S81, if it is determined that j=y, the wireless communication means 74 receives connection destination information for the terminal device 7 from the base station to which the terminal device 7 is connected via the antenna 71A (step S83), and outputs the received connection destination information to the control means 76.

[0496] Then, after step S83, the operation of terminal device 7 ends.

[0497] In the flowchart shown in Figure 30, steps S73 to S78 correspond to the terminal device 7, when it is the destination of the base station, scanning and receiving frames transmitted using one beam k of the base station across y beams 1 to y according to the scanning schedule for k=1 to x.

[0498] Then, when terminal device 7 is the destination of the base station, the measurement results {MR_1~MR_y}_1~{MR_1~MR_y}_x received when a frame transmitted using beam 1~beam x of the base station is sent to the base station (see step S78).

[0499] Furthermore, in the flowchart shown in Figure 30, steps S79 to S82 correspond to sequentially transmitting frames using y beams 1 to y when the terminal device is the source of the beam-based frame transmission.

[0500] When the terminal device is the source of a beam-based frame, the base station scans the beam through x beams 1 to x and creates a measurement result for each frame transmitted using beams 1 to y of the terminal device 7. Therefore, in the flowchart shown in Figure 30, if it is determined in step S81 that j=y, the terminal device 7 does not create a measurement result and proceeds to step S83.

[0501] The operations of terminal devices 8 and 9 are also performed according to the flowchart shown in Figure 30.

[0502] In this embodiment of the invention, the operation of the control device 1 may be implemented by software.

[0503] In this case, the control unit 1 includes a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory).

[0504] The ROM then stores the program Prog_A, which consists of each step in the flowchart shown in Figure 26 (including the flowchart shown in Figure 25).

[0505] The CPU reads program Prog_A from ROM and executes it to control the coordinated beam scanning of base stations 2-6 and terminal devices 7-9. RAM temporarily stores measurement results and other data.

[0506] Furthermore, program Prog_A may be recorded on a recording medium such as a CD or DVD and distributed. When a recording medium containing program Prog_A is inserted into a computer, the computer reads program Prog_A from the recording medium and executes it to control the coordinated beam scanning of base stations 2-6 and terminal devices 7-9.

[0507] Therefore, the recording medium on which program Prog_A is recorded is a computer-readable recording medium.

[0508] Furthermore, in this embodiment of the invention, the operation of base stations 2 to 6 may be implemented by software.

[0509] In this case, each of the base stations 2 to 6 is equipped with a CPU, ROM, and RAM. The ROM stores the program Prog_B, which consists of each step in the flowchart shown in Figure 27 (including the flowcharts shown in Figures 28 and 29).

[0510] The CPU reads program Prog_B from ROM, executes the program Prog_B, and performs beam-based frame transmission and beam-based frame reception at each of the base stations 2 through 6.

[0511] Furthermore, program Prog_B may be recorded on a recording medium such as a CD or DVD and distributed. When a recording medium containing program Prog_B is inserted into a computer, the computer reads program Prog_B from the recording medium and executes it to perform beam-based frame transmission and beam-based frame reception at each of the base stations 2 to 6.

[0512] Therefore, the recording medium on which the program Prog_B is stored is a computer-readable recording medium.

[0513] Furthermore, in this embodiment of the invention, the operation of terminal devices 7 to 9 may be implemented by software.

[0514] In this case, each of the terminal devices 7 to 9 is equipped with a CPU, ROM, and RAM. The ROM stores the program Prog_C, which consists of the steps in the flowchart shown in Figure 30.

[0515] The CPU reads the program Prog_C from ROM, executes the read program Prog_C, and performs beam-based frame transmission and beam-based frame reception for each of the terminal devices 7-9.

[0516] Furthermore, the program Prog_C may be recorded on a recording medium such as a CD or DVD and distributed. When a recording medium containing the program Prog_C is inserted into a computer, the computer reads the program Prog_C from the recording medium and executes it to perform beam-based frame transmission and beam-based frame reception in each of the terminal devices 7 to 9.

[0517] Therefore, the recording medium on which the program Prog_C is stored is a computer-readable recording medium.

[0518] In the above, it was explained that base stations 2-6 and terminal devices 7-9 transmit and receive frames using terahertz wave beams to obtain measurement results used for determining the connection between base stations 2-6 and terminal devices 7-9. However, in the embodiments of this invention, the invention is not limited to this, and base stations 2-6 and terminal devices 7-9 may also transmit and receive frames using millimeter wave beams to obtain measurement results used for determining the connection between base stations 2-6 and terminal devices 7-9.

[0519] Furthermore, although it was explained above that base stations 2-6 and terminal devices 7-9 transmit and receive frames using beams in the planar direction, the embodiments of this invention are not limited to this, and base stations 2-6 and terminal devices 7-9 may transmit and receive frames using beams controlled in the height direction as well as the planar direction.

[0520] In this embodiment of the invention, the control means 12 that creates the first scanning schedule or the second scanning schedule described above constitutes the "creation means".

[0521] Furthermore, in this embodiment of the invention, the control means 12 that executes steps S251 to S261 in Figure 25 constitutes a "determination means".

[0522] Furthermore, in this embodiment of the invention, the communication means 27 that receives the scanning schedule via the backhaul line BHC constitutes the "receiving means".

[0523] Furthermore, in this embodiment of the invention, the control means 26 that determines whether or not the base station 2 is the destination of a beam-based frame constitutes a "determination means".

[0524] Furthermore, in this embodiment of the invention, the beamforming means 23, wireless communication means 24, measuring means 25, and control means 26 that execute the flowchart shown in Figure 28 constitute the "communication means".

[0525] Furthermore, in this embodiment of the invention, the beamforming means 71 and wireless communication means 74 that perform step S71 in Figure 30 constitute a "receiving means".

[0526] Furthermore, in this embodiment of the invention, the control means 76 that performs step S72 in Figure 30 constitutes a "determination means".

[0527] Furthermore, in this embodiment of the invention, the beamforming means 73, wireless communication means 74, measuring means 75, and control means 76 that perform steps S73 to S82 in Figure 30 constitute a "communication means".

[0528] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Industrial applicability]

[0529] This invention applies to programs to be executed by communication systems, control devices, base stations, terminal devices, and computers. [Explanation of Symbols]

[0530] 1 Control device, 2-6 Base stations, 7-9 Terminal devices, 10A, 10B, 10C Communication systems, 11, 27 Communication means, 12 Control means, 13 Database, 21A, 22A, 23A, 71A, 72A, 73A Antennas, 21-23, 71-73 Beamforming means, 24, 74 Wireless communication means, 25, 75 Measurement means, 26, 76 Control means.

Claims

1. m (where m is an integer greater than or equal to 2) base stations that perform wireless communication, n (where n is an integer of 2 or more) terminal devices connected to some or all of the m base stations, The system comprises m base stations and a control device connected by a backhaul line, The control device transmits a scanning schedule to the m base stations for coordinating the m base stations and the n terminal devices to scan the beam. The m base stations transmit the scan schedule received from the control device to the n terminal devices. When m is smaller than n, The m base stations and n terminal devices cooperate to perform a first beam scanning process for all of the m base stations, in which the n terminal devices synchronously scan the beam to receive a frame transmitted from one of the m base stations using one beam based on the scanning schedule, and the first receiving process is performed for all beams scanned by the one base station. When m is greater than or equal to n, A communication system comprising the m base stations and the n terminal devices, which cooperate to perform a second beam scanning process for all of the n terminal devices, in which the m base stations synchronously scan the beam to receive a frame transmitted from one of the n terminal devices using one beam based on the scanning schedule, and the second beam scanning process is performed for all beams scanned by the one terminal device.

2. The communication system according to claim 1, wherein when m is less than n, in the first receiving process, all base stations except the one base station among the m base stations maintain a sleep state based on the scanning schedule.

3. The communication system according to claim 2, wherein, when m is less than n, in the first receiving process, the frame includes destination identification information, source identification information, and the source beam number.

4. When m is less than n, in the first reception process, each of the n terminal devices that received the frame detects the received signal strength at the time of receiving the frame and detects the number of the source beam from the frame, associates the detected source beam number with the received signal strength to create a measurement result, and transmits the created measurement result to the base station to which it is connected. The communication system according to claim 3, wherein n base stations, each connected to the n terminal devices, transmit n measurement results to the control device.

5. When m is smaller than n, The communication system according to claim 4, wherein the control device performs a connection determination between the base station and the terminal device based on the n measurement results received from the n base stations.

6. The communication system according to claim 5, wherein the control device identifies the number of the beam having the greatest received signal strength in the combination of the base station and the terminal device based on the n measurement results, and determines that the beam having a received signal strength equal to or greater than the threshold is connectable when the received signal strength when the frame having the identified number is received is equal to or greater than the threshold.

7. The communication system according to claim 1, wherein when m is greater than or equal to n, in the second receiving process, all terminal devices other than the one among the n terminal devices maintain a sleep state based on the scanning schedule.

8. The communication system according to claim 7, wherein, when m is greater than or equal to n, in the second receiving process, the frame includes the source identification information and the number of the beam of the source.

9. The communication system according to claim 8, where, when m is greater than or equal to n, in the second reception process, each of the m base stations that have received the frame detects the received signal strength at the time of receiving the frame and detects the number of the source beam from the frame, associates the detected source beam number with the received signal strength to create a measurement result, and transmits the created measurement result to the control device.

10. The communication system according to claim 9, wherein when m is greater than or equal to n, the control device performs a connection determination between the base station and the terminal device based on the m measurement results received from each of the m base stations.

11. The communication system according to claim 10, wherein the control device identifies the number of the beam having the greatest received signal strength in the combination of the base station and the terminal device based on the m measurement results, and determines that the beam having a received signal strength equal to or greater than the threshold is connectable when the received signal strength when the frame having the identified number is received is equal to or greater than the threshold.

12. The communication system according to claim 1, wherein the frame is transmitted using the beam in the millimeter-wave band or the beam in the terahertz band.

13. A control device used in a communication system according to any one of claims 1 to 12, A means for creating the scan schedule by coordinating the m base stations and the n terminal devices connected to some or all of the m base stations, The system includes a communication means that is connected to the m base stations by a backhaul line and transmits the scan schedule to the m base stations using the backhaul line, When m is smaller than n, The creation means creates a first scanning schedule for all of the m base stations, which performs a first beam scanning process for all beams scanned by the one base station, in which the n terminal devices synchronously receive a frame transmitted from one of the m base stations using one beam, while scanning the beam. When m is greater than or equal to n, The creation means creates a second scanning schedule for all of the n terminal devices, which performs a second beam scanning process for all beams scanned by the one terminal device, in which the m base stations synchronously receive a frame transmitted from one of the n terminal devices using one beam, while scanning the beam. The communication means is a control device that, when the creation means creates the first scan schedule, transmits the first scan schedule to the m base stations using the backhaul line, and when the creation means creates the second scan schedule, transmits the second scan schedule to the m base stations using the backhaul line.

14. The control device according to claim 13, further comprising determination means for determining whether a connection between the base station and the terminal device is possible based on a first measurement result measured at the n terminal devices when the m base stations and the n terminal devices scan the beam according to the first scanning schedule when m is less than n, and determining whether a connection between the base station and the terminal device is possible based on a second measurement result measured at the m base stations when the m base stations and the n terminal devices scan the beam according to the first scanning schedule when m is greater than or equal to n.

15. The first measurement result includes (x × y) received signal intensities and (x × y) beam numbers, which are the beam numbers of each of the x beams 1 to x, when each of the n terminal devices scans the beams to y (y is an integer of 2 or more) beams 1 to y and receives each of the frames transmitted using the x beams 1 to x. The control device according to claim 14, wherein the second measurement result includes (x × y) received signal intensities when each of the m base stations scans its beams to the x beams 1 to x and receives each of the y beams 1 to y, and (x × y) beam numbers which are the beam numbers of each of the frames transmitted using the y beams 1 to y.

16. A base station used in a communication system according to any one of claims 1 to 12, A receiving means that receives the scanning schedule by coordinating the m base stations and the n terminal devices connected to some or all of the m base stations, A determination means for determining whether the base station is the source or destination of a beam-based frame based on the aforementioned scanning schedule, A base station comprising: when the determination means determines that the base station is the source of the frame, a communication means that sequentially transmits the frame using x (where x is an integer of 2 or more) beams 1 to x; and when the determination means determines that the base station is the destination of the frame, a communication means that receives the frame transmitted using one beam transmitted from one of the n terminal devices by scanning the x beams 1 to x for all of the n terminal devices.

17. A terminal device used in a communication system according to any one of claims 1 to 12, A receiving means that receives the scanning schedule by coordinating the m base stations and the n terminal devices connected to some or all of the m base stations, A determination means for determining whether the terminal device is the source or destination of a beam-based frame based on the scanning schedule, A terminal device comprising: a terminal device that, when the determination means determines that the terminal device is the source of the frame, sequentially transmits the frame using y beams 1 to y (where y is an integer of 2 or more); and a communication means that, when the determination means determines that the terminal device is the destination of the frame, receives the frame transmitted using one beam transmitted from one of the m base stations by scanning the y beams 1 to y for all of the m base stations.

18. A program to be executed by a computer in the control device of the communication system according to any one of claims 1 to 12, The creation means includes a first step of creating the scan schedule by coordinating the m base stations and the n terminal devices connected to one or all of the m base stations, The communication means is connected to the m base stations by a backhaul line, and the computer is instructed to perform a second step of transmitting the scan schedule to the m base stations using the backhaul line. When m is smaller than n, The creation means creates a first scanning schedule for all of the m base stations, which in the first step, performs a first receiving process for all beams scanned by the one base station, in which the n terminal devices synchronously receive a frame transmitted from one of the m base stations using one beam, while scanning the beam; When m is greater than or equal to n, The creation means creates a second scanning schedule for all of the n terminal devices, which in the first step, performs a second receiving process for all beams scanned by the one terminal device, in which the m base stations synchronously receive a frame transmitted from one of the n terminal devices using one beam, while scanning the beam. The communication means is a program to be executed by a computer, which in the second step transmits the first scan schedule to the m base stations using the backhaul line when the creation means has created the first scan schedule, and transmits the second scan schedule to the m base stations using the backhaul line when the creation means has created the second scan schedule.

19. A program for a computer to be executed according to claim 18, wherein the determination means causes the computer to further execute a third step in which, when m is less than n, it determines whether a connection can be made between the base stations and the terminal devices based on a first measurement result measured at the n terminal devices when the m base stations and the n terminal devices scan the beam based on a first scanning schedule, and when m is n or greater, it determines whether a connection can be made between the base stations and the terminal devices based on a second measurement result measured at the m base stations when the m base stations and the n terminal devices scan the beam based on a first scanning schedule.

20. The first measurement result includes (x × y) received signal intensities and (x × y) beam numbers, which are the beam numbers of each of the x beams 1 to x, when each of the n terminal devices scans the beams to y (y is an integer of 2 or more) beams 1 to y and receives each of the frames transmitted using the x beams 1 to x. The second measurement result includes (x × y) received signal intensities and (x × y) beam numbers, which are the beam numbers of each of the y beams 1 to y, when each of the n terminal devices transmits a frame using the y beams 1 to y, and each of the m base stations scans its beams to the x beams 1 to x and receives each of the frames transmitted using the y beams 1 to y. This is the program to be executed by the computer according to claim 19.

21. A program to be executed by a computer at the base station of the communication system according to any one of claims 1 to 12, The receiving means performs a first step of receiving the scanning schedule by coordinating the m base stations in the communication system with some or all of the n terminal devices connected to some or all of the m base stations, The determination means performs a second step of determining whether the base station is the source of a beam-based frame or the destination of a beam-based frame based on the scanning schedule, A program to cause a computer to perform the following steps: when the determination means determines that the base station is the source of the frame, it sequentially transmits the frame using x (where x is an integer of 2 or more) beams 1 to x; and when the determination means determines that the base station is the destination of the frame, it receives the frame transmitted using one beam of one of the n terminal devices by scanning the x beams 1 to x for all of the n terminal devices.

22. A program to be executed by a computer in the terminal device of the communication system according to any one of claims 1 to 12, The receiving means performs a first step of receiving the scanning schedule by coordinating the m base stations in the communication system with some or all of the n terminal devices connected to some or all of the m base stations, The determination means performs a second step of determining whether the terminal device is the source or destination of a beam-based frame based on the scanning schedule, A program to cause a computer to perform the following steps: when the determination means determines that the terminal device is the source of the frame, it sequentially transmits the frame using y beams 1 to y (where y is an integer of 2 or more); and when the determination means determines that the terminal device is the destination of the frame, it receives the frame transmitted from one of the m base stations using one beam, scanning the y beams 1 to y for all of the m base stations.

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